A list of some fediverse-enabled event platforms.
Gancio
A shared agenda for local communities.
Mobilizon
Mobilizon is a tool that helps you find, create and organize events.
You can also create a page for your groupwhere the members will be able to get organized together.
Open source, built and maintained by French not-for-profit Framasoft, who also make the Fediverse enabled video platform PeerTube.
Gathio
Self-destructing, shareable, no-registration event pages.
Built by Darius Kazemi, who also makes the Hometown Mastodon fork.
Public hosted version https://gath.io/