3Blue1Brown — Essence of Linear Algebra
Visual intuition for vectors, matrices, determinants, eigenvalues, and abstract spaces. Short chapters that make the geometry of linear algebra click before you dive into the algebra-heavy stuff.
MIT — Gilbert Strang, 18.06 Linear Algebra
The classic full lecture series from MIT. Strang explains row reduction, subspaces, orthogonality, eigenvalues, and SVD with unmatched clarity. Pair with his book if you want exercises.