I went through my subscription list on FreeTube and filtered these out (the list was much lengthier initially :p)
- Alt Shift X — well detailed and narrated videos about fantasy series such as Dune, ASOIAF.
- Captain Disillusion — very well made videos about VFX.
- Computerphile — computer science twin of Numberphile; neat videos about the field with a wide range of guests.
- EthosLab — pretty much the only Minecraft creator I still watch; witty, quiet and virtually the same for a long time.
- hbomberguy — well known video essayist, easily one of the best in the platform
- Jacob Geller — another quality essayist, exploring different themes, such as horror
- Lemino — very well known creator focusing on mysteries, with incredible narration and stunning visuals
- LockPickingLawyer — very simple, to the point and informative channel about locks and lockpicking; also virtually unchanged for years
- Oversimplified — great overviews of major history events and periods, with funny narration and visuals
- Tantacrul — fairly unknown essayist on music, with well researched material and nice takes :P
- Then & Now — possibly my favorite atm (alongside hbomberguy); extremely well researched and presented video essays about history, politics and philosophy; very underrated imo
Adding onto what's already on the thread, you can try look at the newer Element Call, which is an implementation of Matrix's native calls.
I've been using it a bit recently, since Jitsi seems to have stopped working reliably for me (to be frank, I've not put much effort into debugging it yet). It works well, but it's still early stage, lacking some features Jitsi has. If that one works for you, I recommend you stick to it.