Foundler - Online hackathon weekends. Attend every other week.
Founders Nation - Find or become a startup cofounder
CoFoundersLab - Meet 250,000+ entrepreneurs online
Ship That Shit - Join 3 no BS events to help you ship that shit
Co-founder Question Cards - Questions to ask your co-founder to know each other better.
Huntathon - Browse and submit Product Hunt Global Hackathon projects