Server Fault - Server Fault is a Q&A site for system administrators and IT professionals that's free.

ForumFree - ForumFree allows you to create a forum or a blog in a few simple steps.

Sapien - Sapien is a Web3 social network that gives users control of their data, rewards content creators, and fights fake news.

Proboards - ProBoards is a host of free forums with customer service.

Poal.co - A free speech based link and comment aggregation platform.

Disciple - Grow, engage and monetise your community with Disciple community software. Get your own branded community platform on Web, iOS and Android