Nitter

Federated microblogging server.

Advanced forum / community solution based on Ruby and JS.

Delightfully simple forums. Flarum is the next-generation forum software that makes online discussion fun again.

Forum software built for the modern web.

Knowledge-based community software. You can use it to quickly build your Q&A community for product technical support, customer support, user communication, and more.

Link aggregator for the fediverse (alternative to Reddit).

Distributed social networking server.

Decentralized app-like microblogging server/SNS for the Fediverse, using the ActivityPub protocol like GNU social and Mastodon.

Pixelfed is an open-source, federated platform alternate to Instagram.

Flexible kit for private social networks.

Lightweight commenting server written in Python and Javascript. It aims to be a drop-in replacement for Disqus.