@redlemace On the top of my head I know of these projects:
@endurain and Wanderer (https://wanderer.to/)
I've hosted both of them and they work very good. They serve slightly different purposes: Wanderer is more focused on the social and sharing part, while endurain is more for personal fitness tracking.

@irmadlad If you like to tinker(or even if you don't), you can try out trillium. It is kinda like Obsidian but completely #foss.
While the original Repo is not maintained anymore, there is a very active community fork called TriliumNext

@gedaliyah maybe @delta could be interesting. I found the quite intuitive and well documented. Only thing missing is out-of-the-box calls and video chat. You need a webrtc capable instance for that, I believe.

@delta @gedaliyah That's awesome! I'm looking forward to it!