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
I still don't think it's there, but development hss been fast, so a lot has changed and improved in the last couple of months.