MySocialApp - Seamless Social Networking features for your app
Hamster Pad - A social network built on top of Slack
Manyverse - A social network off the grid
Doof - Share your hopes and dreams.
Mastodon - Mastodon is a decentralized, open source social network. This is just one part of the network, run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome!
sup3rS3cretMes5age - A safe, simple tool for one-time (self-destructing) messages