1.25x1.25u Keycaps?

[vince19]

Check the title, lol
I want a non-1u square keycap for one of my thumb keys for my keyboard, but I'm not sure where to find keycaps like this.
Are there stores that sell 1.25x1.25u keycaps (or something similar, preferably 1.5x1.5u or maybe 2x2u), or do I have to make it my own? Like with 3D printing or using a mold or something, I don't even know how that'll work.

[Findecanor]

There do exist 2×2u keys for Point-Of-Sale keyboards (i.e. cash registers), but those keys fit four switches in a grid. You'd have to use very light springs, or remove springs from some of the switches, and the key would be quite wobbly either way.

I don't think I have ever seen any 1.25×1.25u or 1.5×1.5u keycaps for sale separately.

However, some vintage electronic typewriters have had had four 1×1.25u function keys in a column spanning five rows. (4×1.25 = 5)

There has also been the odd mechanical keyboard that has had a fat space-bar, with one or more matching modifier keys.
The very ugly Freewrite Wordrunner has a fat Alt Gr  key that is almost 1.25×1.25u.

[Qamaz]

Excellent breakdown of the vintage and POS hardware options! It really highlights how niche a 1.25x1.25u square keycap size is. Sounds like 3D printing or modified casting is the only real way forward for vince19 if they want that exact size for their thumb key. Thanks for sharing these rare hardware trivia points!