ChannelSync - Discord is great, we know it, but unfortunately it acts as a gateway for information openess.
Jamform - Collect form submissions without a server or database.
Flarum - Flarum is the next-generation forum software that makes online discussion fun. It's simple, fast, and free.
Linen - Business Tools, Collaboration, and Slack Tools
Discourse - Discourse is an open source discussion platform built for the next decade of the Internet.
OneUp - Schedule and automate posts on Facebook, Instagram, Twitter, Pinterest, LinkedIn, and Google My Business.