PocketLock is described as 'turns screen Off when phone is in pocket, but keeps games and apps alive and running' and is a Battery Saver in the System & Hardware category. There are four alternatives to PocketLock for Android, YouTube, F-Droid and Mac. The best alternative is NewPipe, which is both free and Open Source. Other great apps like PocketLock are Battery GO Helper (Freemium), Clicker for YouTube (Paid) and SongTube (Free, Open Source).
NewPipe is a lightweight YouTube front-end for Android. It doesn't need the YouTube-API or any Google Play Services, as NewPipe only parses the YouTube website in order to gain the information it needs.
Battery GO Helper allows you to lock and black out screen without stopping Pokemon GO process. In this case you can save battery life and you to safely put your phone in pocket. Features: 1. Automatical detect when Pokemon GO (Ingress) app start
SongTube is a new beautiful and fast application made in flutter, it supports YouTube audio and video downloading at any quality, In-App YouTube Browser, audio conversion, Playlists and an Audio tags editor.