This is a video by 3blue1Brown, a math youtuber. He has a variety of videos from personal interest to more education focused. This specific video is part of his linear algebra series, and sets up the later videos by carefully explaining what a vector represents in linear algebra, and what common operations on them represent.
This video supplements my learning on the topic by approaching math in a different direction. He does very little calculations or any example problems, and instead focuses heavily on what the concepts behind them represent. He does this very effectively by also using a calming art style that is reasonably entertaining while not being too distracting. This focus on concepts and visualization combines well for an effective video.