Smart STEM

Dr. Natoshia Anderson has a Stemming in Stilettos Podcast, is pretty passionate about girls in STEM, making learning very accessible to all income groups, and is invested in STEM Mentoring Programs and speaking across the country.

Summer Passport Digital Fun

Khan Academy - Lots of Math Resources, and ability to login and track as a parent or teacher for free at plenty of levels. 

Jeremy Fielding

Smarter Every Day

Mark Rober

Rich Rebuilds - Tesla Mechanics

Adam Savage - Tested

MinutePhysics

Numberphile

Practical Engineering

Crash Course - Multiple Liberal Arts and Science Subject Youtube Universe - Some topics are a bit more mature, maybe 4th Grade and Up, all the way to High School chemistry, literature, philosophy, and civics. Fantastic community of learners!