Company Music Future Ltd created these great apps:
Piano Lessons & Learn, Drums Lessons & Learn, Learn Piano Skills - Chords Scales Arpeggios Lessons & Pracice Music with Metronome Teaching, Learn Drum Skills - Practice Tab Flames Strokes Fills Rudiments Paradiddles Lessons with Metronome Teaching, Purely Metronome, Banjo Lessons & Learn, Mandolin Lessons & Learn, Ukulele Lessons & Learn, Violin Lessons & Learn, Viola Lessons & Learn, Cello Lessons & Learn, Double Bass Lessons & Learn, Fiddle Lessons & Learn, Learn Irish Trad Folk Songs with Purely Fiddle, Learn American Folk Songs with Purely Fiddle, Bouzouki Lessons & Learn, Lute Lessons & Learn, and others..