Here’s a list of ActivityPub services that are not Twitter-like, along with a description of what each service does:

• Pixelfed - image sharing
• Peertube - video sharing
• NodeBB - forums
• Lemmy - forums
• WriteFreely - blog
• Friendica - Facebook-like macroblog
• Hubzilla - macroblog / CMS
• Funkwhale - audio
• ActivityPub for WordPress (Plugin) - CMS
• ActivityPub for Drupal (Plugin) - CMS
• ActivityPub for xwiki (Plugin) - wiki
• ActivityPub for Discourse (Plugin) - forums
• Kbin - forums
• Mbin - forums
• Bookwyrm - book reviews
• Owncast - video streaming
• Pinetta - pins
• Nextcloud - data storage
• Plume - blog
• Castopod - podcasts
• Mobilizion - events
• Flohmarkt - classifieds
• Loops - video sharing
• Gancio - events
• Piefed - forums
• wafrn - Tumblr-like blog
• Lotide - forum / link aggregator
• Postmarks - social bookmarking
• Manyfold - 3D print sharing
• Ghost - CMS
• Brutalinks - link aggregator

There’s a lot more stuff, so let me know what I may have missed.