Where do I find illustrators as collaborators rather than just freelancers/for hire?

As a challenge, I decided I'd rather work on making something physical rather than another digital product.

I'm building a product that showcase interesting stories -- that brings me to I'm looking to find interested illustrators who are looking to bring visibility to their portfolios as a share of the product rather than just for contract/pay. It's also an open project -- I'm not the client necessarily with strict requirements. Leaning more as someone who's interested in doing the legwork, pre launch, sourcing, marketing whatever it takes to sell it.
If I were seeking a developer, I'd likely be on IH, but where do I find designers and how do I filter among them?