The Royal Conservatory has a series of theory apps available on iOS that correlate to their Celebrate Theory books. Thus far, there are five apps available: Prep, 1, 2, 3, and 4. (Luckily, while these apps correlate to the RCM program, you do not necessarily have to use the theory books to use the apps!)
Like many apps out there, students cannot sign in to track their progress, so progress is tracked by filling out this music lab assignment sheet.
Level 4 includes eight different categories: (1) pitch & notation (2) rhythm & meter (3) scales (4) intervals (5) chords (6) music history (7) terms & signs (8) melody & composition. You can get a free version with limited access (or purchase individual levels for $1.99). To use this app for music labs, you will need to purchase the all-access pass ($8.99).
Each download includes two to three lab pages. You can purchase each level separately or as a bundle.