Family, friends, former coworkers/ bosses, local business networking groups, meetup groups (especially the non-tech ones), volunteering, sports clubs, IRC/ slac

Family, friends, former coworkers/ bosses, local business networking groups, meetup groups (especially the non-tech ones), volunteering, sports clubs, IRC/ slack channels in your stack, hackernews, etc. Chances are if there is person you can think of that's "successful" they would happily talk to you about a project or point in the direction of one of their friends that needs a hand. Hell you could probably cold email some of the people from indie hackers if all the rest wasn't working.