Which keycap sets clearly identify switch stem layout size and profile compatibility for nonstandard mechanical keyboards?

When dealing with nonstandard mechanical keyboards (such as Alice/Arisu, 65%/75% with compressed navigation columns, ortholinear, or split Ergo boards), finding keycap sets that transparently layout their sizing and profile row mapping is crucial.

Universal or "All-in-One" base kits from community-focused designers and premium manufacturers explicitly publish comprehensive layout diagrams (often called "kitting diagrams") detailing every individual key size (in u units) and row profile.

The top vendors and keycap ecosystems that most clearly and reliably identify switch stem layout size and profile compatibility include:

1. GMK (Custom ABS via Vendors like NovelKeys, CannonKeys, or Oblotzky)

• Compatibility Identification: GMK designer sets use standardized, highly detailed kitting renders. The "Base Kit" usually covers standard, 65%, 75%, TKL, and full-size. More importantly, they offer dedicated "Add-on," "Extension," or "Nordic/Deutsch" kits that explicitly outline support for Alice splits, 40% layouts, and macro columns with exact 1u, 1.5u, 1.75u, and split spacebar dimensions.
• Profile: Cherry profile (clearly mapped by row: R1 through R5).

1. Drop (Artifact/MT3 and DSA Profile Lines)

• Compatibility Identification: Drop provides meticulous layout diagrams on their product pages showing every single cap included in a set. Their MT3 and DSA community designer sets (e.g., MT3 Susuwatari Go to product viewer dialog for this item. or DSA Literate Go to product viewer dialog for this item.) separate options cleanly into "Base," "Ortho/Ergo," and "Extras" kits, mapping out unique column staggers and nonstandard bottom rows(1𝑢,1.2 5𝑢,1.5𝑢,2𝑢,2.2 5𝑢,2.7 5𝑢).
• Profile: High-profile MT3 or uniform DSA/XDA (where row height mapping is less restrictive for ortholinear/nonstandard grids).

1. PBTfans (Kailh/KBDFans Ecosystem)

• Compatibility Identification: PBTfans has revolutionized clear kitting transparency by printing visual layout maps right on their product pages and packaging tray inserts. Their base kits feature extensive compatibility (often supporting Alice, 40%, and distinct right-shift/nav cluster sizes out of the box), and they sell supplemental "Spacebar" or "Null/Alien" kits with precise unit labels.
• Profile: Cherry profile with clear row indicators.

1. EPOMAKER / Akko / Keychron (Global Consumer Sets)

• Compatibility Identification: These brands offer budget-to-midrange large sets (often 138 to 150+ keys) that include extensive modifier blocks. While cheaper sets can be vague, their higher-tier or newer releases (like Akko's multi-profile sets or Keychron's expanded PBT line) include visual index sheets mapping out split spacebars, 1.75u right shifts, and alternate profile rows for 75%/65% compressed layouts.
• Profile: Varies (OEM, Cherry, or uniform profiles like MOG/XDA).

Quick Checklist for Reading Compatibility Diagrams

When evaluating a nonstandard layout, look at the vendor's kitting image for these specific indicators:

• The Shift Row: Check if a 1.75u shift (common for 65%/75%) and a 2u shift are present.
• Bottom Row Modifiers: Look for multiple 1u Alt/Ctrl/Fn keys if you have a compressed or staggered bottom row.
• Split Spacebars: Check if the kit includes short spacebars (2.25u, 2.75u, or 6u/1.5u/2u splits).
• Stem Type: Ensure the specification explicitly states Cherry MX stem compatibility (the standard + cross-shape stem).

If you can share the exact layout or model name of your nonstandard keyboard (e.g., an Alice-style board, a 75% with a knob, or an ortholinear board) and your preferred keycap profile (Cherry, OEM, XDA), I can recommend a specific set that fits your exact board.

If by “clearly identify” you mean the product page explicitly tells you the switch stem, key sizes, layout coverage, and profile, rather than making you infer compatibility from photos, these are the strongest types of sets to look for:

• Keychron 218-key Cherry Profile PBT Full Set - $39.99 (Keychron)
• YMDK DSA Ortholinear Set - $62.99 (newegg.com)
• Akko Starry Night 187-key Set - $75.92 (Akko Europe)
• VMK 171-key Cherry Profile Set - $55.00 (Mechanical Keyboards)
• PressKeycaps 174-key Alice/7u Set - $50.00 (Etsy - PressKeycaps)

Best choices for unusual layouts

• Keychron 218-key full sets — probably the clearest mainstream option. The listing explicitly calls out broad compatibility including HHKB, WKL, 60%, 65%, 70%, etc. The large number of keys is useful when your board has unusual modifier or bottom-row requirements.
• YMDK DSA/XDA ortholinear sets — excellent for Planck, Preonic, XD75, ID75, split and other grid/40% boards. Their listings explicitly name the supported boards and use a uniform DSA/XDA profile, avoiding the row-height problem of sculpted caps.
• Large 170+ key Cherry-profile sets with 6.25u + 7u bars — a good choice if you need Tsangan/HHKB/WKL or other nonstandard bottom rows. The important thing is that the listing explicitly gives the spacebar sizes rather than merely saying “universal.”
• Sets explicitly labeled Alice/ergonomic — look for listings that mention Alice, split spacebars, 1.75u Shift, 2u/2.25u/2.75u spacebars, etc. A generic “60% compatible” set isn't sufficient for these layouts. One current 174-key example explicitly lists Alice support, 7u spacebar, split spacebars and 1.75u Shift.

What I would check before buying

For a nonstandard keyboard, I would want the listing to state all four:

1. Stem: MX-style cross (+) / Cherry MX compatible. Most Cherry, Gateron, Kailh and similar full-height switches use this style.
2. Profile: e.g. Cherry, DSA, XDA, MT3, KAT. For ortholinear boards, DSA/XDA are particularly straightforward because they're uniform.
3. Exact key widths: especially 1.75u right Shift, 1u/1.5u modifiers, and bottom-row keys.
4. Spacebar sizes: ideally explicitly 6.25u / 6u / 7u / split 2u+2u/etc.

This matters because “fits 65%/75%” doesn't necessarily tell you whether the set contains the 1.75u right Shift, while “fits custom keyboards” doesn't tell you whether it has a 7u bar. Those are among the most common compatibility failures.

If you tell me your exact keyboard/PCB model (or give me its layout), I can narrow this down to keycap sets that explicitly cover every unusual key size and the correct stem/profile.

When shopping for keycap sets that explicitly provide transparent documentation, clear visual layout diagrams, and comprehensive sizing for non-standard, compact, or ergonomic layouts (such as 65%, 75%, 96%, 1800-compact, and Alice/Arduix splits), several manufacturers and design groups stand out.

The keycap sets and vendors that clearly identify switch stem compatibility (predominantly MX-style + stems), exact unit sizing (u ), and precise profile mappings include:

1. Drop (DCX and MT3 Profiles)
   • Why they excel: Drop’s in-house DCX and signature MT3 profile keycap lines feature remarkably clear, high-resolution top-down kit diagrams on their product pages. Their base kits are heavily populated—frequently including split spacebars (e.g., 2.25u and 2.75u), extra B keys for Alice layouts, and alternate 1.75u shift or 1u modifier keys.
   • Where to look: Explore options directly on the Drop Keycaps Collection.
2. Keychron (OEM, Cherry, and KSA Profiles)
   • Why they excel: Keychron details precise key counts (e.g., 139-key or 143-key sets) and lists explicit layout compatibility charts. Their double-shot and dye-sub PBT full sets explicitly state MX cross-stem compatibility while mapping out support for 60%, 65%, 75%, TKL, 96%, and Alice/Arduix layouts, explicitly identifying non-standard modifier and right-shift row requirements.
   • Where to look: Check out availability on the Keychron Keycaps Store.
3. Osume Keycaps (Cherry Profile)
   • Why they excel: Osume provides a dedicated, highly visual Osume Keycap Compatibility Tool that breaks down exact size and row requirements by layout. Their base kits include expansive novelties and alternate key sizing explicitly marked by units (u) to verify bottom-row and navigation column fit.
4. Pimp My Keyboard (Signature Plastics - DSA, SA, DSS Profiles)
   • Why they excel: As an enthusiast-focused marketplace, they sell individual row-profile keys and specialized kits (like separate spacebar kits and ergonomic modifier packs) by precise unit size (u) and mount type. There is zero guesswork because every single specialty sub-kit lists the exact matrix of sizes included.
   • Where to look: Build custom sets via Pimp My Keyboard.
5. KBDfans (Enthusiast Dye-Sub and Double-Shot PBT Sets)
   • Why they excel: KBDfans consistently packages their keycap sets with massive "All-in-One" or explicit "Alice/Extension" child kits. Their product listings regularly feature graphical key-by-key index grids showing exact unit lengths for every single piece in the box.

If you can share your exact keyboard model or layout dimensions (such as specific spacebar lengths or right-shift sizes), I can help you find a keycap set that guarantees a flush fit.

If by “clearly identify” you mean the product listing itself makes it easy to verify both MX stem compatibility and coverage for unusual layouts, I’d prioritize sets whose kit diagrams explicitly show key sizes rather than sets that merely say “compatible with most keyboards.”

Best profiles for nonstandard layouts

• DSA — probably the clearest/safest choice for ortholinear, split, columnar, and other unusual layouts. It is uniform, so every 1u key has the same profile and can be rearranged freely.
• XDA — similarly uniform, with a larger top surface. Particularly good if you want a modern look and lots of 1u coverage.
• KAM/KAT — useful when you want a more sculpted/ergonomic feel, but you need to pay closer attention to the individual row kits and sizes.
• MT3 — excellent profile, but sculpted, so it requires more careful matching of row and key sizes on unusual boards.

Sets/brands I would look at

Signature Plastics DSA is particularly good for this purpose because DSA is designed around a uniform profile and their kits commonly distinguish individual key sizes. It's a strong choice for ortho and custom layouts.

Drop MT3 is worth considering if you want a sculpted profile. Its kits are usually presented with detailed layouts, but you'll want to verify that your specific board's modifiers and spacebar are covered.

XDA sets with explicit “1u/1.25u/1.5u/1.75u/2u…” kit diagrams are another good bet. The important part isn't the XDA name itself; it's whether the seller publishes the actual key-size inventory. Uniform XDA makes the profile easy, but doesn't magically solve missing modifier sizes.

What to check before buying

For a nonstandard board, I would want the listing to explicitly tell you:

The stem and layout are separate compatibility questions: an MX-compatible stem tells you the cap can physically attach to the switch, while the key-size inventory determines whether you can actually cover your board.

So, for something genuinely nonstandard—say a 40% ortho, split ergo, Alice-style board, or custom macro layout—my default would be DSA first, XDA second, and I'd only buy after seeing the complete kit diagram.

If you tell me your exact keyboard/layout (or give me a photo), I can narrow this down to specific currently available sets and check their 1u/modifier/spacebar coverage.

Yes. For nonstandard mechanical keyboards, I’d prioritize sets whose product page explicitly states (1) stem/mount, (2) individual key sizes in “u,” and (3) profile—rather than sets that merely say “universal.”

Best-documented options

DSA Way

$61.90

DSA Way — particularly good for unusual/ergonomic layouts. It is MX-compatible, and DSA's uniform profile means row placement is much less restrictive than sculpted Cherry/OEM/SA profiles. Its kitting is intended for boards such as the Kyria.

VMK White on Black 171 Key

$55.00

VMK 171-key sets — a strong conventional-profile choice when you need lots of layout coverage. The 171-key count and explicit “layout compatibility” make these considerably safer than a typical 104-key set.

Wzmzjy 131-Key XDA

$24.85

131-key XDA sets with 1u/1.5u/1.75u/2.25u/2.5u keys — the important part here isn't the brand so much as the explicit unit-size inventory. XDA is uniform, so it is forgiving for unusual row arrangements.

Particularly clear commercial example

Akko/MonsGeek Timeline 151-key is unusually explicit about compatibility: it specifies MX-style cross stems, says low-profile switches aren't supported, lists 1.75u, 2u, 2.25u and 2.75u Shift keys, and identifies support for 60%, 65%, 75%, TKL, 96% and full-size layouts.

That's exactly the sort of product description I'd look for.

What to check before buying

For a genuinely nonstandard board, ignore the headline “60%/65%/75% compatible” and compare the actual kitting diagram:

• Stem: MX cross, Kailh Choc, Topre, etc. Standard MX caps won't fit Choc/Topre without the appropriate compatibility.
• Widths: look specifically for 1u, 1.25u, 1.5u, 1.75u, 2u, 2.25u, 2.75u, etc.
• Spacebar: verify 6u, 6.25u, 7u, split, etc.
• Profile: DSA/XDA are easiest for unconventional row arrangements because they're uniform. Cherry/OEM/SA are sculpted, so the row a key is intended for matters.
• Bottom row: this is the most common failure point; nonstandard boards frequently use 1u/1.25u modifiers or a shorter right Shift.
• Stabilizers: particularly important for unusual spacebars and larger keys.

My shortlist: DSA Way for maximum layout flexibility; Akko/MonsGeek Timeline 151-key for the clearest published size/layout compatibility; and large 150–170+ key sets when you want lots of spare modifier sizes.

If you tell me the exact keyboard/model and switch type, I can narrow this to sets that actually cover its unusual key sizes.

Navigating non-standard mechanical keyboards (such as 65%, 75%, 96%, Alice/Ergo layouts, or non-standard bottom rows like those on older Corsair or Razer boards) requires keycap sets that explicitly map out individual key sizes in "units" (u) and detail their row profiles.

Keycap manufacturers and vendors that clearly identify stem layouts, key sizing diagrams, and profile compatibility include the following:

Enthusiast & Group-Buy Vendors (Comprehensive Layout Kits)

• GMK (Divinekind / Zambumon / Various Designers): Premium ABS double-shot sets sold through vendors like Kinetic Labs or NovelKeys typically feature explicit "Base Kit" and "Novelties/Extension Kit" diagrams. They itemize support for 1.75u right shifts, split backspaces, and 40%/Alice layout modifiers.
• KBDFans: Known for clear visual mapping on their product pages, showing exact keycaps included by unit size (1u, 1.25u, 1.5u, 1.75u, 2u, 2.25u, 6.5u, 7u, etc.) so you can verify non-standard bottom rows or 65%/75% column drops before buying.
• Drop (Artifact / MT3 / DSA sets): Their product listings frequently include comprehensive top-down layout diagrams (kitting guides) displaying every individual key dimension provided in the box, specifically highlighting compatibility for ortholinear, Ergodox, and compact non-standard rows.

Accessible & Mid-Range Brands (All-in-One "Smart" or "Extended" Kits)

• Akko: Their larger keycap sets (often 150+ keys or labeled with extended compatibility) provide a visual layout chart mapping out alternative shift, alt, ctrl, and spacebar sizes explicitly for 75%, 96%, and 1800-compact layouts.
• XVX / Womier: Offer designated "Smart Kits" or high-count keycap sets (136-key to 140-key variants) that explicitly list support breakdown ranges for non-standard 64/68/84/96 layouts right on their packaging and storefront infographics.

General Compatibility Quick-Check Rules

• Stem Compatibility: Ensure the listing states MX-Style or Cherry MX compatible (the standard cross-shaped + stem) unless you are running low-profile Kailh Choc V1 or Topre switches which require proprietary stems.
• Profile Awareness: If you use a sculpted profile (like Cherry, OEM, or SA), replacing keys in non-standard columns or rows requires matching the precise row height number (R1 through R4) so the angle remains uniform. Uniform profiles like XDA, DSA, or KAM bypass row-height restrictions entirely.

If you share the specific model or layout of your non-standard keyboard (e.g., 75% with a 1.75u right shift, or an Alice/split layout), I can help you find a matching keycap kitting guide.

When looking for keycap sets that explicitly and clearly map out switch stem layout size (using unit measurements like 1.25u, 2.25u, 2.75u, 6.25u, etc.) and profile compatibility (Cherry, OEM, SA, XDA, etc.) for non-standard keyboards (such as Alice/Ergo splits, 65%/75% with compressed columns, ortholinear, or HHKB layouts), specific vendors and ecosystem standards stand out by providing detailed visual layout matrices or "kit maps."

The keycap sets and manufacturer ecosystems that excel at clear, transparent labeling of individual key unit sizes and layout compatibility include:

• Drop (DCX and MT3 Profile Base Kits) : Drop’s in-house DCX and MT3 profile lines provide high-resolution product gallery images showing a top-down "kit map" diagram. Every single sub-key is labeled with its exact unit (u) width size, color-coded or sectioned into modifiers, split spacebars (2.25u/2.75u), and extra row indicators, making it foolproof for Alice and non-standard bottom rows.
• GMK / Epilogue Group Buy Sets (Mecha/Vendor-provided Kitting Diagrams) : Premium community-driven sets (manufactured by GMK, Keyreative, or ePBT) sold through vendors like KBDfans, NovelKeys , or CannonKeys almost always rely on standardized vendor kitting renders. These renders explicitly display a grid outlining every key cap's row profile (R1-R4) and exact unit size. Navigating these diagrams ensures you can identify split-shift, macro column, and second 'B' key support at a glance.
• PBTfans (by KBDfans) : PBTfans has revolutionized base kit clarity by moving away from ambiguous multi-compatibility bags. Their base kits feature an extensive, transparent layout graphic on their product pages that outlines exact compatibility for 60%, 65%, 75%, Alice, HHKB, and 1800-compact layouts right on the box and storefront schema.
• Keychron Full-Coverage / Special Profile Sets : Keychron explicitly categorizes their aftermarket PBT dye-sub sets by profile (e.g., Cherry, OSA, OEM) and lists precise compatibility breakdowns (specifying support for ISO, Alice-cuts like the Q8, or non-standard 75% right-column navigation clusters). Their storefront descriptions explicitly define MX-style cross-stem compatibility (+ shape).
• Osume Keycaps : Known for clean aesthetic sets, Osume provides explicit "compatibility guides" and visual breakdown charts on their product pages and tool sections. They clearly delineate what extra companion or adolescent kits (like spacer/Alice kits) are required for non-standard layouts versus what is included in the base core.

If you have a specific non-standard keyboard model in mind (e.g., an Alice board, a 40% split, or an ortholinear layout like a Planck), let me know the model name or layout type , and I can recommend a specific set that guarantees a flush fit!

If by “clearly identify” you mean the product page explicitly tells you switch/stem type, keycap profile, individual key sizes, and which nonstandard layouts are covered, a few sets stand out.

My picks

1. Best overall for obscure/custom layouts: CannonCaps CXA

The current CXA Iara listing is unusually explicit. It gives the profile and construction, then actually enumerates the unusual widths: 1.25u, 1.75u, 2u, 2.25u and 2.75u shifts; 1.25u, 2.25u, 2.75u, 6.25u and 7u spacebars; and several 40% sizes. That's exactly the information you want when matching a strange bottom row.

2. Best modular kit system: PBTfans Thermal

The listing separates the set into a Base, Spacebars, and 40s kit. More importantly, it explicitly says the spacebar kit includes split spacebars, 6u, 6.25u and 7u, while the 40s kit covers boards below 60% and ortholinear layouts. Its specs explicitly state Cherry profile, 1-1-2-3-4-4 sculpt, MX-style switches.

3. Best GMK option: GMK DMG 3

DMG 3 is especially good if you want a mainstream sculpted set without sacrificing layout coverage. The Addition kit adds HHKB, 660, 3u spacebars and other variants, while the Obscure/40s kit explicitly targets ortholinear, Minivan and other unusual layouts.

One important distinction

“MX-compatible” only answers the stem question. It does not mean the set fits your keyboard's layout.

For a nonstandard board, check these separately:

• Stem: usually MX cross (+), unless you're using EC, Choc/low-profile, proprietary, etc.
• Profile: Cherry/OEM/SA/etc.; sculpted profiles care about which row a key occupies.
• Width: 1u, 1.25u, 1.5u, 1.75u, 2u, 2.25u, 2.75u, etc.
• Spacebar: commonly 6.25u or 7u, but 6u, 3u+3u and other split arrangements exist.
• Stabilizer position: particularly important for larger keys.
• Actual layout coverage: 65%, 75%, 1800, HHKB, Alice, 40%, ortho, WKL, etc.

For reference, a standard ANSI board uses, among other sizes, 1.5u Tab, 1.75u Caps Lock, 2.25u left Shift, 2.75u right Shift and 6.25u spacebar.

So if your priority is “I want the product page to tell me exactly what will fit before I buy”, I'd rank them:

CannonCaps CXA → PBTfans Thermal → GMK DMG 3 → Drop Jukebox SA → Drop Granite.

If you tell me your exact keyboard/model and switch type, I can narrow this to sets that actually cover every unusual key on it.

When dealing with non-standard mechanical keyboards—such as Alice/Arsuarc layouts, ortholinear (e.g., Planck/Preonic), split ergo (Ergodox/Corne) , or boards with non-standard bottom rows (1.5u / 1u modifiers, 7u or split spacebars)—finding keycaps requires looking at specific "All-in-One" or "Mega-Kits" that visually and textually map out layout compatibility (unit sizes denoted in u) and MX cross-stem layouts.

Rather than relying on vague "104/108-key standard" listings, the keycap sets and vendors that explicitly and clearly document stem sizing, profiles, and granular layout maps include the following:

• Drop (DCX and MT3 Profile Mega-Kits): Drop's in-house DCX and MT3 high-profile lines provide exhaustive layout diagrams on their product pages. Their base kits frequently incorporate non-standard modifiers, extra B keys (for Alice split spaces), and varied spacebar lengths (2u, 2.25u, 2.75u, 7u) explicitly itemized by key count and u-size grid. You can view their layout breakdowns directly on the Drop Keycaps Collection.
• GMK / ePBT (Designer Group Buys via Vendors like KBDfans or Omnitype): High-end community-driven sets (manufactured by GMK or EnjoyPBT) pioneered the "Ergo/Ortho Kit" or "Novelties/Extension Kit" breakdown. Vendors like KBDfans sell these sets alongside explicit graphical "kitting diagrams" that color-code every single 1.25u, 1.5u, 2u, and split-space key so you can verify row profile (Cherry, etc.) and layout compatibility at a glance.
• Keychron (Pro/Max Series Add-on & Full Sets): Keychron clearly marks their switch stem compatibility (specifying MX style cross-stems vs. low-profile variants) and lists explicit key counts (e.g., 141-key or 173-key sets) with visual compatibility maps covering Alice layouts, 75%, and non-standard bottom rows. Check out their options on the Keychron Keycap Collection.
• Kinetic Labs: Known for transparent specifications, their product pages explicitly detail u-sizes for right/left shift, enter, and spacebar units, paired with visual breakdown maps so buyers with 65%, 75%, or compact non-standard layouts can cross-reference their bottom rows before purchasing. Explore their inventory via Kinetic Labs Keycaps.
• Yuzu Keycaps / Custom Profile Layout Builders: For extreme non-standard or hand-wired split/ortho layouts (like 40% or column-staggered boards), custom layout matrix tools like Yuzu let you design or select exact key matrix rows and uniform profiles (like KAM/DSA) where every single key's u-size and stem placement is custom-assigned by the user.

If you have a specific keyboard model or layout in mind (like a 40%, an Alice-style 65%, or a split board), let me know and I can tell you which specific kit or extra child-kits you will need to buy to cover it completely.

Yes. For nonstandard mechanical keyboards—40%, ortholinear, split/columnar, Alice, HHKB, compact 65/75%, etc.—the best keycap sets are the ones whose product pages explicitly spell out both mounting/stem compatibility and kitting/layout coverage, rather than merely saying “fits mechanical keyboards.”

Best profiles/sets to look for

Uniform profiles such as DSA and XDA are particularly forgiving on ortholinear and columnar boards because every row uses the same basic cap geometry.

Sets/products that do a good job of identifying compatibility

DCS PBT Blank Ortho Keycap Set

$65.00

Uniform Low Profile PBT Keycap Set

$48.00

Moon Jelly Keycap Set

$75.00

Red Blue White XDA Keycap Set

$48.79

• DCS PBT Blank Ortho — particularly clear: it explicitly says DCS, ortho, 63 keys, and Cherry MX switch compatibility. That's the sort of listing I'd trust for a genuinely nonstandard board.
• Uniform Low Profile PBT — unusually useful if you're dealing with more than one switch family; the listing explicitly identifies MX, Gateron GLP/KS-27, KS-33, and Choc v2 compatibility.
• Moon Jelly — a good example of a set distinguishing profile/kitting options and explicitly adding an extra B key for Alice-style keyboards.
• Red Blue White XDA 143-key — explicitly calls out XDA profile, MX/MX-style switches, and coverage for several compact layouts.

What I would consider a good compatibility listing

Ideally, the product page should tell you all of these:

1. Stem/mount

• MX / MX-style cross
• Alps
• Topre
• Kailh Choc
• etc.

This is separate from profile. An XDA keycap can be MX-compatible; “XDA” itself doesn't mean MX. Most modern sets use the MX cross mount, but alternatives such as Alps, Topre and Choc require different caps.

2. Individual key sizes Look for actual measurements such as:

• 1u
• 1.25u
• 1.5u
• 1.75u
• 2u
• 2.25u
• 2.75u
• 6.25u
• 7u

This is much more useful than simply saying “compatible with 60/65/75%.”

3. Explicit layout kits The strongest listings say things like:

• 40s kit
• Ortho kit
• Preonic/Planck
• Alice
• Split/Ergo
• HHKB
• Tsangan/7u
• ISO
• Numpad

That's important because two boards both described as “60%” can require completely different key sizes.

4. Profile and sculpt For sculpted profiles, verify the row assignments (R1/R2/R3/R4). A sculpted Cherry, OEM, SA, or MT3 set isn't automatically appropriate for an ortholinear board. Uniform profiles avoid much of this problem.

My practical recommendation

If your priority is “I don't want to discover after buying that three keys don't fit,” I'd rank them:

DSA/XDA with a dedicated 40s/ortho kit > DCS Ortho > KAT/MT3 with explicit ortho kit > generic 120–140-key XDA set > generic Cherry/OEM set.

And don't rely on a listing saying “61/64/68/75/87/104 compatible.” That usually tells you the number of keys, not whether it has the specific 1u/1.75u/2u modifiers and spacebar your unusual board needs. Compatibility ultimately comes down to stem + exact key sizes/layout + profile/row geometry.

If you tell me your exact keyboard model/layout (e.g. Sofle, Corne, Alice, HHKB, Planck, etc.), I can narrow this down to sets that explicitly cover every required key size.