My current recommendations. Items within each category are ordered by preference.

Books

Flatland: A Romance of Many Dimensions
(free on Kindle!?)
Thinking, Fast and Slow
How Not to Be Wrong: The Power of Mathematical Thinking

Podcasts

Very Bad Wizards
Making Sense Podcast (with Sam Harris)

Youtube Channels

3Blue1Brown
Steve Mould
standupmaths
TylerMcGinnis.com

Youtube Playlists

Essence of linear algebra - 3Blue1Brown
Imaginary Numbers are Real - Welch Labs
Essence of calculus - 3Blue1Brown

Youtube Videos

Quantum Computing for Computer Scientists

Comics!

Too many to list here - needs its own page