What I think are underrated channels, alreayd listed channels removed. Some have irregular schedules but still worth checking out.

Animals

• Cal Falcons: live stream of a falcon nest on a rooftop
• Deep Look: small world biology (PBS)
• Journey to Microcosmos: smaller world biology (Hank Green)
• Saveafox: domestic fox rescue

Science/Tech

• Captain Dissilusion: video editing vs disinformation
• Cody's Lab: currently building a "Mars" habitat
• The Friday Checkout: weekly tech highlights

Music

• CSGuitars: electric guitar science
• First of October (Andrew Huang, Rob Scallon): very constrained songwriting
• Rhythm in Africa: sub-Saharan instruments
• Wataru Kousaka: Japanese instruments

Pop culture

• Game Changer: improv comedy as a game show (CollegeHumor)
• Overanalyzing Avatar: "This man is dead. Appa killed a man"
• Solid jj: voiced superhero comic parodies

History

• Jay Foreman: British culture and/or maps
• Lateral with Tom Scott: lateral thinking puzzle as a podcast
• Objectivity: very interesting objects (Brady Haran)
• Sam O'Nella Academy: badly researched and animated trivia satire