Gab - Gab is an ad-free social network dedicated to free speech.
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Friendica - Decentralisation - Privacy - Interoperability
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
PixelFed - PixelFed is a federated image sharing platform, powered by the ActivityPub protocol.
Bigtent - BigTent is a web-based organization and communication portal for groups.