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

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

Pixelfed - Decentralized social media

Learn more about Pixelfed, the free and open-source decentralized photo sharing social media platform

Pixelfed
@atomicpoet No offense. But, the interaction on these services is next to none. Mastodon is limited enough. But, Pixelfed and so on is next to zero. Which shows me that even the people using Mastodon aren't using these other services. Noble cause? Perhaps. But, I would hate to be the one investing time and money.
@LScottSpencer Sorry, what do you mean interaction is next to none? So far today, I have over 1,600 interactions on this post alone. Hell, you’re talking to me right now.
@atomicpoet I have over 20,000 on my recent Threads post. But, I was speaking more of Pixelfed and Peertube.

@LScottSpencer Well, Pixelfed just released its mobile app last week. It takes time to build a community there, but it doubled in size over the last month – so it’s coming along nicely.

Peertube is a different story because video is quite expensive, which means the bulk of server owners limit registrations on their servers – which also limits the network effect.

All that said, you can build a bustling community on all those services but the skillset is quite different from a service like Threads. You cannot depend on figuring out what the algorithm likes, and thus scale your content for maximum engagement. Instead, you have to take the pre-algorithmic approach of building relationships with people instead of hoping a bunch of randos will just suddenly find your content in their feed.