arkTube

Supports downloading ALL resolutions including 1080p, 1440p, 4K and 8K [1]
Supports downloading audio [1]
Supports downloading playlists [1]
Download accelerator support [1]
Automatically merges thumbnail(artwork), tags and other metadata when downloading audio
Provides option to merge metadata to video downloads [1]
Supports downloading videos as VP9 format [1]
Supports downloading audio as Vorbis / Opus codec [1]
Supports downloading 50fps / 60fps
Supports resuming paused downloads

/* Powerful engine */

arkTube uses one of the most actively developed open-source project in the world : youtube-dl
Supports downloading all options
Optimized downloader for faster downloads
Download without any loss to quality
Consistently updated for best compatiblity

** Video that requires adult authentication or login, marked as hidden from public, is a live-stream may be unsupported.
** VP9 is a new video codec from Google that improves video quality and reduces overall file size. Galaxy S6 and Galaxy Note 5 currently supports VP9.
** 50fps / 60fps with 1440p+ resolution is only provided as VP9.
** If you run into issues, make sure you're running the latest version and contact the developer with the URL of the video.

[1] These features require additional donation package to be installed

/* Contact */

Email : qkrwngud825@gmail.com
Twitter : @arter97_dev

/* Downloads and links */

arkTube APK
arkTube and the Donation package has been tested with hundreds of different CTS-certified ROMs.
If you have a problem activating arkTube's pro features, switch to another ROM or do a refund within the Play store.
It's highly unlikely that I might be able to help you.
If you missed the 2 hours refund window, email me personally.
Donation package

/* Screenshots */

arter97.com