Taking notes inside vim for vim to remember mappings

Fixed title: Taking notes inside vim for vim-specific stuff so I can remember how to do stuff

I'd like to take notes inside of vim to remember commands and keymappings. I currently use help and a file in my .vim, but it's somewhat burdensome. For example, I only use a couple of fold methods. I don't want to search the help file for it when I can just write a quick note. The note should be callable in vim, so I could do something like :Notes or :Notes fold-all.

Does this exist? I'm not sure what to search. I suppose I could grep the notes file.