This app was mentioned in 5 comments, with an average of 1.80 upvotes
Couldn't find it on their main website, maybe I'll keep digging though. I'd definitely be interested to test it!
EDIT: Seems to be in the Play Store, https://play.google.com/store/apps/details?id=org.herac.tuxguitar.android.activity.admob I'd prefer it to be in F-Droid if possible though. I'll have a poke around tomorrow and see if I can yank it from Play Store and install it without Play Services...
Check out Tux Guitar. It will open GuitarPro and PowerTab files, and it's free/open source.
Check out TuxGuitar — it works with GuitarPro files and is free/open-source
https://play.google.com/store/apps/details?id=org.herac.tuxguitar.android.activity.admob
I can see there is even tux guitar for Android.
https://play.google.com/store/apps/details?id=org.herac.tuxguitar.android.activity.admob