Foundler - Online hackathon weekends. Attend every other week.
CoFoundersLab - Meet 250,000+ entrepreneurs online
Perpetua Project - Curated events for investors, operators & founders
HackHub - Host tech events and hackathons with ease 👨💻🛠
FounderWheel - Meet potential co-founders everyday
Confs.tech - Open source list of tech conferences: JS / Ruby / Data etc.