Leonard Susskind is kind of a boss, and as a resource for personal education ascends to new heights: He has presented and had recorded a number of video lectures that are now freely available, which are dedicated to giving the viewer a “theoretical minimum” exposure to modern physics. They presuppose a certain level of mathematical training, namely linear algebra and partial differentiation. I have personally vetted Classical Mechanics and Quantum Entanglements Part 3 (horribly misnamed, as it’s actually about Special Relativity and Electromagnetism) and am working on Quantum Entanglements Part 1.
But wait! There’s more: Since I kind of make a hobby out of this kind of stuff (more on that later), I’ve found two sets of collections of notes about those very Susskind lectures: here and here. The latter, if completed, will also feature notes about Walter Lewin’s MIT lectures, but that’s another post.