The number of commercial open source projects increase every day, yet the model is still hiring completely in-house and if any outsider wants to contribute without pay, they're welcome too.

I've heard there is a crypto project that is willing to pay after a while so I just wanted to learn about the existence of similar initiatives.

This kind of arrangement is beneficial to both owners and participants:

For owner, they get access to a larger pool and for participants they can contribute entirely on their own terms with micro-contracts (e.g. 1 open issue = 1 micro-contract)