I use YouTube almost every day, and subscribe to a lot of channels. Over the years, I've collected a list of my favorite channels. They're mostly science, history or trivia related channels. As you can imagine, I love learning new things, even if just scratching the surface of a topic.

Some of the channels listed would fit in multiple categories, but I've organized them after the topics I primarily watch them for. The channels in each category are ordered in descending order, starting with the "best" (according to me). Categories appear in alphabetic order.

Computer science & math

Computerphile

As a computer engineering student, this channel does a good job in explaining various concepts and algorithms in a clear and simple way. You don't need to know any programming to follow most of these videos.

Tom Scott

Tom's channel covers many topics. Travel, language, technology and more. I began following him after he appeared in some videos on Computerphile, but he also posts some very interesting computer science videos on his own channel.

Numberphile

I don't watch all of Numberphile's videos, but the vast amount of content on this channel is crazy. My favorites are the ones on prime numbers, but there's plenty more worth watching.

Engineering

SmarterEveryDay

This is easily one of my top three favorites. Destin finds something that he wants to know more about, and then explores it to great depths. His series on helicopters is a favorite of mine. This guy is a real rocket scientist, too! If you don't follow him already, stop reading, and go do so now.

Engineerguy

Many other science related youtube channels could probably be tagged as "edutainment", as they focus just as much on keeping you entertained throughout their videos, as they do on actually teaching you something. Engineerguy is somewhat different. While he's not boring by any means, he focuses more on explaining things thoroughly. Want to know how are soda cans made, and how do clicker pens work? Go watch his videos.

History / psychology / thought provoking

Vsauce

Hey Vsauce, Michael here! Sounds familiar? Vsauce's videos are almost always viral hits. Things you didn't know you wanted to know... He digs into all sorts of topics, and and the result is never boring to watch.

Bite Size Psych

This is one of the lesser known channels on my list. One that I think deserves more views. How do you get more productive? What processes influence our decisions? These are some questions this channel tries to answer (and does so quite well, in my opinion).

Caspian Report

Another channel that deserves more views than it gets. This guy makes fairly long YouTube videos, mostly on history and geopolitics. As the name of the channel implies, there is a slight predominance of videos on countries, conflicts and history around the Caspian sea, but not overwhelming. They still cover the same topics for regions and countries all over the world. The videos lack references to source material, which make them unsuitable as sources for academic work. Still, as a "history layman", I find them very interesting and easy to follow.

Others

CGP Grey

If you've used YouTube in the last few years, you've probably already watched some of his videos. Grey puts out new videos quite infrequently, but the quality is always top notch. Stick figures and simple graphics, combined with a great script, makes for a some very interesting videos. He's great at breaking down complicated concepts, and making them understandable to anyone.

In a Nutshell - Kurzgesagt

Kurzgesagt recently changed their name to "In a Nutshell". They haven't been making videos for as long as many of the other channels listed here, but have grown at an enormous rate. Their animation style is quite unique, and very professional. Combine that with great narration and interesting topics, and you've got a very solid package.

Ahoy

Ahoy is a gaming channel, but not your average "let's play" or anything like that. They're a history channel, with a gaming focus. That includes the history of games as a whole, but also elements found in games, like weapons. Do weapons work the same way in real life, as they're presented in video games? What has contributed to making certain weapons appear in so many games? I haven't watched a single video on this channel that I didn't like.

WonderWhy

This channels is sort of a "CGP Grey lite". Most of what I said about CGP Grey, applies here. While the videos may not feel quite as polished, they are still pretty solid. Definitely worth checking out if you like CGP Grey.

CrashCourse

I could have put this under "Science", but the channel is so diverse, I put it here. Rather than making one video per topic, they produce full series of 40-ish videos on things like biology, world history, economics etc. The episodes are of good quality, and there's always source materials for you to dig further into.

The Brain Scoop

If you faint just looking at bones, blood and tissue, you probably shouldn't watch these videos. They cover topics like taxidermy, fossils, bio diversity etc. If you do find these things fascinating, like I do, go check them out.

CaptainDisillusion

This guy's channel is dedicated to debunking viral videos, by breaking them down, and showing how illusions, computer graphics and similar techniques are used to fool the viewer. His intros are a little cheesy, and over the top, but not too bad.

Science

Veritasium

While this channel has shifted its focus a little in later years, I still enjoy watching their new videos. Especially the videos where Derek talks to people on the street about a certain phenomena (often physics related). Often about things most people don't quite understand, and then he goes on to explaining how it really works. It's a style of presenting that works very well, and makes you think about the world differently.

Applied Science

This guy takes the viewers with him into his shop, where he makes all kinds of machines and tools. How about modding a scanning electron microscope, or making a hot chocolate gun? This guy is a true maker.

MinutePhysics

Short videos about physics. That's it. Using simple, hand drawn illustrations, and condensing various concepts down to the bare essentials, this channel's videos are always a pleasure to watch.

MinuteEarth

From the same people who make MinutePhysics, these videos are largely the same, in the way they look and feel, but on slightly different topics. This channel focuses on biology, bio diversity, climate change. Yeah, anything related to the way our planet works, really.

NurdRage

This channels is a bit like Applied Science, in that he explains how things work. However, this channel is more focused towards chemistry, rather than electronics. Not my primary interest, but I still watch most of his videos.