SearXNG does, I think…any others? Looking around for other engines that aren’t US-based, though I guess DDG is still considered acceptable for LibreWolf’s default engine. Bangs are incredibly useful!
Kagi (paid) advertises a huge list of bangs with the option to customise them yourself.
Brave Search has !bangs and an independant search index. Kagi relies heavily on it.
I’m currently using Startpage, which is dutch
I also use them, and have liked the results.
Probably because they pull from Google
Searxng uses bangs but you have to double them up (i.e. !!aur btop or !!ddg search).
I love how your first example was AUR.
I use arch BTW.
Andisearch admitts, among other commands, also !bangs
Andi is 100% free and anonymous, no logs, no ads, no tracking, random proxie, sandboxed results.