Here are some YouTube videos Logan Joseph and myself have made to aid students in understanding course material in physics and mathematics and to fill in the gaps for undergraduates interested in mathematical physics!
Mathematical Aspects of Classical Mechanics
Topology as a Generalization of Real Analysis
An Introduction to the Laplace Equation
An Introduction to Vector Bundles
An Introduction to Countability and Separation Axioms in Topology
Free Particles and Bound States in Quantum Mechanics
Curvature and the Einstein Field Equations
Important Distributions in Probability Theory
Manipulating Differential Forms
Limit Theorems in Probability Theory