This app was mentioned in 3 comments, with an average of 1.00 upvote
This is the best app I installed this year, basically free occupational therapy:
https://play.google.com/store/apps/details?id=com.rubycell.perfectguitar&hl=en_US
I've seen a lot many on play store. https://play.google.com/store/apps/details?id=com.rubycell.perfectguitar