PodKoi - Find podcasts to be interviewed on & guests to interview.
Huntathon - Browse and submit Product Hunt Global Hackathon projects
Speaker Directory by HeySummit - Guests for your next event or podcast (or submit yourself!)
Foundler - Online hackathon weekends. Attend every other week.
Zoho Backstage - Plan, run, and analyze your event— all from one place
Confs.tech - Open source list of tech conferences: JS / Ruby / Data etc.