@mhoye One of my favourites that I use a lot and that always amazes people at first is a vim feature. Mark a column across a couple of lines, and insert what you type in all lines in that column.
It comes in handy when you comment out code line by line. Not necessary.
I think it's cool because it demonstrates that marking text can be done in ways other than the usual, and also inserting text (or deleting) can happen in multiple places simultaneously.
A private instance for the Finkhäuser family.