TubeMate

V3 is available on 

https://apkpure.com/store/apps/details?id=devian.tubemate.v3

[TubeMate - The fastest and most famous YouTube downloader]
TubeMate allows you to download YouTube videos so you can watch them offline!
* Visit tubemate.net to get the latest TubeMate because TubeMate will disappear from the market.
* Fast download mode(with multiple connections for a download)
* Multiple download resolution options
* Background, multi-download
* Resume downloading
* Convert to MP3 (powered by MP3 Media Converter)
* YouTube search and related videos suggestions
TubeMate YouTube Downloader enables you to quickly access, search, share, and download YouTube videos.
Because downloading always happens in the background, you can go on watching YouTube, surfing the Internet, tweeting, and listening to your music as you download.