Free open source self-hostable file storage and collaboration platform. This is the project that Nextcloud was forked from, but the original is still going as its own thing.
Fediverse address:
@ownclouders@mastodon.social
Tagged: Collaborative
HedgeDoc
Free open source collaborative markdown editor. HedgeDoc is web-based and you can host it yourself if you want to. (HedgeDoc was previously known as CodiMD.)
Fediverse address:
@hedgedoc@fosstodon.org
NextCloud
Free open source personal cloud software for sharing files, collaborative editing, instant messaging, personal music streaming and lots of other things. It’s extremely flexible thanks to lots of add-on apps that can be installed through the graphical interface. Nextcloud instances can be accessed through web browsers or dedicated apps for all major platforms. You can host a cloud yourself or sign up on an existing instance.
Fediverse address:
@nextcloud@mastodon.xyz
OpenProject
Free open source online project management software, including classic, agile and hybrid management throughout project life cycle.
Fediverse address:
@openproject@fosstodon.org
Wikidata
Free open knowledge base, available for anyone to use on any project. It is collboratively edited like Wikipedia, and its contents is public domain.
Fediverse address:
@wikidata@wikis.world
Gancio
A free open source collaborative online calendar. It allows local communities to share a common calendar that anyone can post events to, even people without an account. (Posts are moderated to prevent spam though.) You can also interact with Gancio through the Fediverse, and it has RSS support for people who want to follow through feed readers.
Fediverse address:
@gancio@mastodon.cisti.org