I've made many interesting playlists in many different subjects including:
Fire,
Water,
Earth,
Infinity,
Paradoxes,
Time,
Light,
Magnets,
The sun,
Life
Sounds,
Sleep,
the brain,
perception,
flight,
and many more.
Tried to alphabetize it...The list of playlists is way too long.
Architecture, Barrages, Biotechnology/Biomimicry, Brain/Mind, Nlood & Other Bodily Fluids, Boredom/Randomness, Creeper Tunes, Disease: Prevention, Research, Cures....etc, Engineering, Enviornmental Songs, Favorites, Food/Drink/Argiculture/Cooking, Evolution, Flight, Humans, Humor (of some sort), Information Technology, Infinity, Liked Videos, Language&Communication, Music, Music 2, Paradoxes, Practical Tips , Robots, Russell Brand, Social Experiments, Spinning Projectiles,Time Dialation,
Maybe that's half of them, maybe not enough half.