3Blue1Brown is a YouTube channel about animating math. Checkout the "Recommended" playlist for some thought-provoking one-off topics, and take a look at the "Essence of linear algebra" for some more student-focussed material.
CultureTalk features video clips of interviews and discussions with people from many different countries and of many different ages and walks of life. Some interviews and discussions are in English. More are in the language(s) of the countries involved. Translations and/or transcripts are given for all non-English video clips. Topics include family, food, education, religious and cultural customs, work, art, sport, travel, and more.
Kideos features safe, funny, screened videos for kids with all their favorite characters. Videos are hosted on YouTube, but Kideos provides a clean, safe interface for children to browse for hand-picked, approved videos.