PixelFed - PixelFed is a federated image sharing platform, powered by the ActivityPub protocol.
Shape Collage - Shape Collage is a photo collage maker software program. Automatically create picture collages in a variety of shapes with just a few mouse clicks. Available for Windows, Mac OS X, and Linux.
Gab - Gab is an ad-free social network dedicated to free speech.
PhotoCollage - PhotoCollage allows you to create photo collage posters from a list of photographs.
Friendica - Decentralisation - Privacy - Interoperability
PhotoSpills - Easy to use PC collage software with unlimited design possibilities.