Nostr, what are some lesser known or less popular apps or websites that you use, that have some social aspects to them, that you'd like to see rebuilt upon Nostr?

For example: Untappd. This app could be rebuilt on Nostr. Badges, location, comments, DMs, events, etc.

Thanks!

(Yes, I'm going to email and contact all of them. I have a cold email pitch that I wrote yesterday that is just about finalized.)