3Blue1Brown (Grant Sanderson)

Grant Sanderson 3Blue1Brown is the gold standard for mathematical visual explanation and has influenced an entire generation of science communicators. The channel focuses on mathematics — linear algebra, calculus, neural networks, Fourier transforms, topology — and consistently explains concepts that students struggle with for years in single 20-30 minute videos using custom-built mathematical animation software (Manim, which Sanderson open-sourced and is now widely used by math educators globally). The Essence of Linear Algebra series and the Neural Networks series are considered the best introductions to their subjects available in any medium. The extraordinary thing about Sanderson work is the depth of the conceptual insight: he does not explain what the derivative is, he explains why the definition was designed the way it was and what intuition it is trying to capture. Subscription count of 7 million understates his influence — the channel work is assigned reading equivalent in university courses worldwide.