Where do you find high-quality affiliates?

I just signed up for Rewardful because I want to try out affiliate marketing, but I figured it would have some kind of built-in affiliate acquisition method, like a 2-sided marketplace sort of thing, where you could promote yourself to qualified potential affiliates in a related category. But that's definitely not the case -- you have to find and sign up affiliates yourself.

So my question is: How do you find high-quality affiliates? For reference, I run Nodewood, so I'm looking specifically for affiliates who can reach early-stage indie hackers, small software app developers, and probably development agencies.