Errant Signal - Thoughtful, intelligent long-form dissections of video game topics.
Extra Credits - Thoughtful, intelligent long-form dissections of video game topics. Animated with cartoon people.
Innuendo Studios - Thoughtful, intelligent long-form dissections of video game topics.
Gaijin Goombah - Dissections of culture in gaming, especially foreign culture and mythological things.
The Film Theorists
The Game Theorists sans isn't ness
VSauce - Explores intriguing ideas about science and mathematics.
PBS Idea Channel - Literally explores ideas. Examines the connections between pop culture, technology, and art. (Encourages viewers to have discussions in the comments and subreddit, then reads and talks about said comments the next week.)
LastWeekTonight - News from last week, presented in a blend of news show host, satire, comedy, poking-fun, and truth bombs.
MinuteEarth - Short earth-science videos animated with stick figure cartoons
minutephysics - Short physics videos animated with stick figure cartoons
AsapSCIENCE - Short science videos animated with whiteboard drawings
Game Grumps
(and many Game Grumps Animated channels e.g. Brandon Turner)
JonTronShow
Continue? - Three guys play a retro game (sometimes not a well known game) for a short time, make improvised jokes, and then give a rating of Continue or Game Over.
WillBits - A Let's Player with very few viewers and a whole lot of talent. He's great and putting fun new voices to every NPC, he's a funny guy, and he rarely gets stuck. No but seriously he's a really fun voice actor and he could use more exposure.