One of my favorite parts of D&D is how much the original stuff is just "nerd-adjacent stuff from the 70s," which definitely includes Kung Fu, psychic powers, and rad-as-hell Satanism
I say this as someone who tried and failed to comfortably integrate the D&D3 monk with "generic fantasy," you can't do it, you can only do gonzo fantasy so you need to add more stuff like the monk. A class for Spocks and Doctors Who. Gray aliens as a player race. Rocket sleds vs pterodactyls.