Could we have a board where we help people look for things?
Half-remembered song lyrics where the OP wants to identify the song, books they read as a child and remember little bits of, old TV shows that they remember some scenes of etc.
It could just be just for remembering things that people half-remember, or it could also be for finding physical stuff (eg a replacement for a lost beloved toy)
I really enjoy threads like this but they tend to be scattered around and often end up in AIBU. There are lots of sub-reddits focussed on this kind of thing (eg "Tip of My Tongue", "Find That Song", "What Song Is This?") and I was thinking that it might be fun and helpful to have a similar board on Mumsnet