Ghostkeys seem like part of a decent approach to this, since it's a "prove contribution without dictating how" system. Crypto/cash/"they gave me a high five, they're cool" are all equally valid, and it's not a proof of work that costs substantial money to operate: https://freenet.org/ghostkey/

Currently it appears centralized, but in principle it'd be pretty easy to shift it to a web of trust instead, and hosts can choose what they allow and how much they value it.

(zero-knowledge proofs seem probably rather important to adopt tho, as right now it'll tie you to a stable pseudonym)