https://pqrs.org/osx/karabiner/
I use it to map the emacs navigation keys for use across the OS, and find it really improves my experience. If you're interested in that set up, I use the following options, which are all listed under Emacs Mode: - Control + PNBF to Up/Down/Left/Right - Control + A/E to Command + Left/Right - Option + B/F to Option + Left/Right - Control + D to Forward Delete
Of course, I have caps lock remapped to Control.
There are also Vi remap options in Karabiner, plus tons of other stuff.
Disclaimer: I'm a bit of an emacs lightweight, so it might be that the remapping options aren't as full-featured as what a more advanced user would like.