MySocialApp - Seamless Social Networking features for your app
Manyverse - A social network off the grid
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
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!
Sociall (Beta) - A secure and private decentralised social network for all.
Android Creator - Make your app for Android phones and tablets