Documentaryz has a good user interface and is very easy to navigate. The videos included in its library are basically YouTube videos but there are also videos from other video hosting platforms. There are several categories that you can browse through to find your content such as Art, Animal and Nature, Business, History, Biagraphy, Military, Media, Funny, Music, Psychology, Environmental, ..and many more.
Documentaryz is free of charge and does not require any installation or software download. You also have the choice whether to open a free account or just use it as a guest user. If you register with them you will have added features such as being able to track your history of videos watched, organize playlists and interact with the community.
If you are a teacher and want some media resources then consider Documentaryz you might find something interesting you can share with your students.