Genuinely surprised a simple, soulbound ERC hasn't emerged on Ethereum by now.

Anyone aware of someone working on one?

Working on Farcaster and Warpcast. Longer thoughts at https://dwr.email

Not an exact answer to your question, but the team at Violet has some interesting thoughts around this and ways to leverage ERC721

https://docs.humanbound.xyz/humanbound/faq

https://mirror.xyz/violetprotocol.eth/lyxVNcwRmejE7a45eJiRiSUtM2MuirXZoKTeZiNWS7c

🟪 #173 | ⌐◨-◨  | Test everything; retain what is good.  

From what I hear though, is that they pivoted

also worth mentioning here…
the soul wallet team
(a smart wallet with social recovery) 

https://www.soulwallet.io/

Yeah this stuff is a better direction than simplistic “soulbound”