The video series made by 3Blue1Brown are fantastic. He crafts visual math videos using an animation engine he has developed to provide great explanations for understanding concepts more deeply. Beyond the technical, his presentation style and insight makes them very motivational to follow.

Series on linear algebra: https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2x...

Animation engine: https://github.com/3b1b/manim