Kurzgesagt is one of our favourite channel: their videos are interesting, well-documented and easy to follow thanks to a nice animation job. Definitely something to recommend for people willing to discover about the great questions of our time - at least on the science level.
They mainly focus on physics, exploring topics linked to space and the universe, but not only. They will often talk about biology, cognitive science and even philosophy. They focus on content and rarely - if ever - promote anything else than their own work. In a nutshell, this is a great channel.