SmallTube

A simple and native YouTube client for iOS.

Features:
- Ad-free watching
- Picture-in-picture with background play. Start playing a video in fullscreen, swipe from the bottom, and access the home screen. The video will continue playing in picture-in-picture. Locking your iPhone will not stop the playback. It works on all iPhones except the SE.

Limitations:
- Only embeddable video can play (most songs and copyrighted material are not available)
- The app requires an API key from the YouTube Data API. You can easily create one for free.