Caps Lock feature is useless. Reuse its key for something useful. Good alternatives:
Esc (if you're a Vim user)
Keyboard layout switch
If you move Ctrl to Caps Lock key, reuse Ctrl for something else.
Programmers might benefit from swapping 1-0 keys to their Shifted versions
). So that you use Shift to produce a digit.
If you use two similar languages, check if one of the layouts have 3rd level keys for another language. (e.g., both ru and uk have 3rd level keys for one another). This way you can use one layout instead of two and input chars from other layout holding right alt.
See X keyboard extension - ArchWiki advanced configuration.
39aldo39/klfc: Keyboard Layout Files Creator—can generate XKB files from a simpler format.