NewPipe - NewPipe is a lightweight YouTube front-end for Android.
FreeTube - FreeTube is an open source desktop YouTube player built with privacy in mind.
Invidious.io - Invidious is an alternative front-end to YouTube.
YouTube - Our mission is to give everyone a voice and show them the world.
Tube Archivist - Your self hosted YouTube media server.
VueTube - A simple FOSS video streaming client aimed to recreate ALL features from their respective apps (and more).