Some of my favorites are from Edward Frenkel and the Langlands Program. In analogy the Langlands Program can be thought of as the "Theory of Everything" of mathematics linking various seemingly disconnected fields together.
Another great video is from 3b1b where he shows Pi somehow emerge from 2 blocks colliding against each other.
Maybe not mindblowing but the Mathologer guy has some good, not so "pop maths" videos. I like this one about the 1 + 2 + 3 + 4 + ... = -1/12 absurdity that they spoke about on Numberphile
It's pretty basic, but for me when I first saw it, I was blown away.
Donald in Mathmagic Land 1959 (https://yewtu.be/watch?v=hl6JDv4ZG7U) - in Technicolor!!