Foundler - Online hackathon weekends. Attend every other week.
TechEvents.co - Tech and startup events aggregator
CoFoundersLab - Meet 250,000+ entrepreneurs online
Facebook Local - Discover places to go and events happening near you
HackHub - Host tech events and hackathons with ease 👨💻🛠
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets