I like the idea, I know that similar things have been long brewing for GMK, for example, Sheraton's new Sky Dolch Modifiers gets close to the uniquely coloured modifiers concept
My .02
1) No Cmd/Meta/Super like keycaps = :(
2) Maybe stick to the core ideals of your set, drop monochrome, and instead add various assorted modifiers instead - If someone is looking for double-coloured modifiers, there are other options
2-a) Or double-down on monochrome, add various modifiers for various usages
3) Coloured arrows could be interesting too
The Git modifiers are super cool, I personally wouldn't use them tho
Another personal opinion, while GMK/Cherry is best, DSA > SA for coding for me, SA looks great, but it's super tall
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Honest opinion, while the set is OSX-hostile, "Chalk, Oblivion, Git" combo could be a big-hit in SA, for coders without OCD - tho it's awfully similar to SA Penumbra