No, there are not other, and I think we should proceed with care. Hosting fees are a burden specially for something that might die, I don't think a Pixelfed instance would be so useful now since the platform in general doesn't have much activity as Mastodon does. On the PeerTube case, it would be nice, but videos require a lot of storage space, increasing hosting fees even more, so it gets complicated.
We also have a Matrix instance, which is hosted by Genzedong people.
A BookWyrm instance where book clubs could be formed around would be a really nice idea.