There are a lot more keycap profiles than just XDA, DSA and SA. See below. There is also G20, Tai Hao Cubic and I'm sure some more that I missed.
A standard bottom row compatible with aftermarket keysets has keysizes like:
1.25 | 1.25 | 1.25 | 6.25 |1.25 | 1.25 | 1.25 | 1.25