Please refrain from posting popsci channels.

Physics and astronomy:

Kavli Institute for Theoretical Physics
https://www.youtube.com/channel/UC6S-TJHOZnwXRhvBd8Ol_1A/

The Canadian Institute for Theoretical Astrophysics
https://www.youtube.com/user/citaseminars/

IAC
https://www.youtube.com/user/IACvideos/

CfA Colloquium
https://www.youtube.com/channel/UCApHNlZLkxmiV95A0ChueYg/

Stanford Physics
https://www.youtube.com/user/StanfordPhysics/

SLAC National Accelerator Laboratory
https://www.youtube.com/user/SLAC/

Institute of Cosmos Sciences UB
https://www.youtube.com/channel/UC8HJ3IYkytEHoAOAF9gYYww/

Lunar and Planetary Institute
https://www.youtube.com/user/LPIUSRA/

JSC Astromaterials Research and Exploration Science
https://www.youtube.com/channel/UCGay_0kl8AlrjvAGTGRoARA/

Keck Institute for Space Studies
https://www.youtube.com/user/KISSCaltech/

UofT AstroTours
https://www.youtube.com/channel/UCTjzCZm5Zz6a_rKhczGB0nA/

Caltech Astro
https://www.youtube.com/channel/UCpslw1KdoUvnCKi0swsb23w/

Nottingham Gravity Group
https://www.youtube.com/channel/UCVlk8Tu1qs6lXEz7Zw-pNnw/

SV Astronomy Lectures
https://www.youtube.com/user/SVAstronomyLectures/

Institute for Gravitation and the Cosmos
https://www.youtube.com/user/PSUGravityInstitute/

Various topics:

Geological Society
https://www.youtube.com/channel/UCzhX_LOB1xUwIDmckTrPOqw/

PSW Science
https://www.youtube.com/channel/UCNiTfOS0R4xai51DTpNL_3A/

UC Berkeley Events
https://www.youtube.com/user/UCBerkeleyEvents/

SETI Institute
https://www.youtube.com/user/setiinstitute/

NASA Astrobiology
https://www.youtube.com/user/NAIVideoResources/

Carnegie Science
https://www.youtube.com/user/CarnegieInstitution/

The Institute for Cross-Disciplinary Engagement at Dartmouth
https://www.youtube.com/channel/UCXgDq9rF0ttB5cd9Ij-KOjg/

Rotman Institute of Philosophy
https://www.youtube.com/user/rotmanphilosophy/