Audiobus: Use your music apps together.
What is Audiobus? — Audiobus is an award-winning music app for iPhone and iPad which lets you use your other music apps together. Chain effects on your favourite synth, run the output of apps or Audio Units into an app like GarageBand or Loopy, or select a different audio interface output for each app. Route MIDI between apps — drive a synth from a MIDI sequencer, or add an arpeggiator to your MIDI keyboard — or sync with your external MIDI gear. And control your entire setup from a MIDI controller.Download on the App Store
Audiobus is the app that makes the rest of your setup better.
Cyber Week Deals - Music Apps (2019)
Here’s one, perhaps: Chool, a character guitar chord reference. I noticed it was 99 cents (US) today, which was less than I saw it for on Friday. Not sure if this was Cyber Monday-only, or if the deal will be carrying on all week.
I haven’t actually tried this one yet, but it looks like a cool way to learn some new chords.