Find A Maker - find a partner for your next project
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.
Findnlink - Find people to work with on your ideas.
Team of Teams - http://teamofteams.io/ digital platform helps young co-founders to match by their professional core values with help of ML.