NewPipe: A free lightweight Youtube frontend for Android.
NewPipe does not use any Google framework libraries, or the YouTube API. It only parses the website in order to gain the information it needs. Therefore this app can be used on devices without Google Services installed. Also, you don’t need a YouTube account to use NewPipe, and it’s FLOSS.
Display general information about a video
Watch YouTube videos
Listen to YouTube videos (experimental)
Select the streaming player to watch the video with
Download audio only * Open a video in Kodi
Show Next/Related videos
Search YouTube in a specific language
Watch age restricted material
Display general information about channels
Subscribe to channels
Watch videos from a channel
… and many more
Although NewPipe only supports YouTube at the moment, it’s designed to support many more streaming services. The plan is, that NewPipe will get such support by the version 2.0.