- turning my CapsLock into escape. As a vim user I use it all the time
- when CapsLock is held it turns into a hyper key. Hyper+e to switch to Emacs window, hyper+b to browser and so on
- creating application independent maps that work on Linux and MacOS: ctrl+w is always "kill last word", super+w to kill a tab or a window
- invoking hammerspoon commands on MacOS that tile windows, bring up window switcher, etc.