On a more physically conventional keyboard without a thumb cluster, esc seems (oddly, given the switch) like a great spot to put a rarely-used key like caps lock.
Tab is a bit of a an odd one. It is useful for printing, but almost entirely useless as an input… so useless in fact that it has been repurposed for auto-complete, which is really useful!
Which leads to my gripe about how web forms and forms in other apps usually ignore tab order and often even the idea of tabbing between input fields altogether.
Also, I've been using tabs for indentation (with spaces for alignment) in code for decades. Though linters are slowly killing that.
Tab is a bit of a an odd one. It is useful for printing, but almost entirely useless as an input… so useless in fact that it has been repurposed for auto-complete, which is really useful!