Idea for enhancement: adding the cheat sheet queries to the autocomplete list (http://danbooru.donmai.us/help/cheatsheet)
I don't know how others browse Danbooru, but I frequently use stuff like rating:, user:, order:, status:, etch. I imagine many others might use these too.
It obviously wouln't be of much use for stuff like id:, width:, height: and so on, since one has to choose specific numbers that cannot be autocompleted, but it could be quite convenient for stuff like status:, user:, order:, rating:, etch.
Anyways, thank you for your excellent work!