Emacs has something called Keywiz https://marmalade-repo.org/packages/keywiz https://marmalade-repo.org/packages/keywiz which will gather your keybindings (incl

Emacs has something called Keywiz https://marmalade-repo.org/packages/keywiz https://marmalade-repo.org/packages/keywiz which will gather your keybindings (including custom ones) and ask them back to you as a quiz. Not as cool as this but I used to play it back in the day and learnt quite a few neat tricks from it.