This is what you are looking for:

Original OG youtube app with audio and video download capability with background playing of youtube videos

[button color=”red” size=”big” alignment=”center” rel=”follow” openin=”samewindow” url=”https://www.mediafire.com/?btb7uciotagazcl”]OG YOUTUBE[/button]

Tube Mate app with download feature and background playing of your youtube videos.

[button color=”red” size=”big” alignment=”center” rel=”follow” openin=”samewindow” url=”https://www.mediafire.com/?btb7uciotagazcl”]TubeMate[/button]

Audio Pocket can be easily found on Play store so i didn’t gave the link for it.

My video on the particular feature: