F-Droid - F-Droid is an interesting alternative for Android users who want to try something different and not have to use the Goole Play store all the time.
Enhancer for YouTube - Tons of features to improve your user experience on YouTube™!
APK Pure - Download apk for Android with APKPure APK downloader. NoAds, Faster apk downloads and apk file update speed. Best of all, it's free
Iridium by ParticleCore - Iridium is an extension built to improve the user experience on the new YouTube Material layout.
APKMirror - Android Market and APK Downloads
ImprovedTube - Allows you to improve and enhance Youtube visually or enable dozens of new features permanently or...