The CtC community is pretty prolific, and if your colors could match theirs that'd be much easier to parse. https://youtu.be/mkomrpQG388?t=212 has most of them all at once, I think palindrome is the only one missing from there.
Also, if your solver could pick up shift for corner marks and control/command for center marks, that'd be a nice quality of life pickup compared to Sudokupad.