Mine are:

Cmd+Shift+V - Stacked clipboard, you can start typing to search or hit a number to choose what to paste (keeps everything you've copied/cut inside jetbrains for a while)

Cmd+Shift+E - Recent locations, you can start typing to search - shows little buffers of where you've been recently

Cmd+Shift+A - Action tab of the command palette - fuzzy search for any command (really the only shortcut you need, other than maybe Shift+Shift for main command palette shortcut)

--- Through the Action bar...

Local History / Local History of Selection - you can start typing to search quite far back the history of all changes of the current file or selection - you can also right click a folder or the project and do the same. Much finer grained than git.

The general concept of being able to search for something and edit directly in the buffer of the search results.