Using Vim key bindings in Onenote

You could edit LaTeX files, with Vim. That would allow you to have more formatting possibilities, while keeping the editing power of Vi. It won't give you a WYSIWYG aspect, though.

It seems that there is an open-source project to make Vim dedicated to editing LaTeX with a plugin: Vim-LaTeX. You could look into that, if interested.

Caution: If you use Win 8 or later, do not use this utility as it will create some trouble - see comments.

Hotkey Commander displays a list of programs with registered hotkeys in addition to other functionality.

It's shareware, so if you only need to see what program has registered which key, you can use free utility Hotkey Explorer, download link is on the same page.