Minitube - Minitube is a YouTube desktop application.
FreeTube - FreeTube is an open source desktop YouTube player built with privacy in mind.
YouView - Browse, watch, convert, and download YouTube videos on your Mac faster, because YouView uses the core technologies of Mac OS X to play instead of Flash allowing video to run smoother on systems with lower specs.
NewPipe - NewPipe is a lightweight YouTube front-end for Android.
YouTube Media Player - Media Player is an open-source project that aims to enhance the overall YouTube experience.
YouTube Vanced - Vanced is a modded version of YouTube with many features such as adblocking and background playback