I think this is one?
nostr:nevent1qqspyzrvkdfgekre7d0jwrnz2klw3zsan8g4zqun528r5g3y60dk47ctsnshr
But it looks like there is no handler information (kind 31990)
Discussion
Seems like it. It’s fairly new and not many clients have implemented it. Only Flockstr for now, I think, but probably no handler event for that kind yet for that client. nostr:npub1zach44xjpc4yyhx6pgse2cj2pf98838kja03dv2e8ly8lfr094vqvm5dy5