Y Combinator Co-founder Matching - YC’s free online platform to help you find your co-founder
Founders Nation - Find or become a startup cofounder
CoFoundersLab - Meet 250,000+ entrepreneurs online
Co-founder Question Cards - Questions to ask your co-founder to know each other better.
CollabFinder - Find cofounders and makers to help build your project
The On Deck Fellowship - An 8-week program for 100 of the best early-stage founders