There actually is a HelpMeFind community (lemmy.ml/c/helpmefind), although it’s dead at the moment. I agree it’s be good to have it up and running.

I used to have a multi Reddit set up which grouped various subs all about helping people either identify things (songs/movies/books/random objects they’d found/etc), find them online to buy, or discover new related stuff (If I Like This), it was quite fun and obviously it helped people. Also meant I discovered a LOT of music that I really liked, but would probably never have heard of.