For the #mathematics inclined or merely #math curious, I've been really enjoying 3blue1brown's youtube channel recently.

https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw

His two "Essence of..." series are quite good.

Essence of Linear Algebra: https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab

Essence of Calculus: https://www.youtube.com/playlist?list=PLZHQObOWTQDMsr9K-rj53DwVRMYO3t5Yr