Here’s a list of people/sites/places i’ve learned a lot from :

elektronaut - Bileam Tschepe. Great tutor of Touchdesigner, lots of good content on his Youtube channel. Perfect for beginners and advanced

Polyhop - Simon Alexander-Adams, aka Polyhop. Really good tutorials, well explained.

Kohui - Superb for learning Touchdesigner tricks and interesting ways of doing things. NotoTheTalkingBall on Youtube

Matthew Ragan - There’s not much he doesn’t know about TD. I learned a lot of GLSL from him. Really good educator.