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 StoreAudiobus is the app that makes the rest of your setup better.
OT Windows Users: New update includes a photo slideshow video app
Great news! Windows has re-introduced it's photo slideshow video app. One of the most disappointing aspects of Windows 10 was their discontinuance of the Power Toys, their old video app among them. The new one seems easy enough to use if you've ever used the old one or Apple's iMovie. No transitions that I am aware of. Really only good for whipping up something quick, (i.e. a song and some album art or a slideshow.) You can access the app from the Photos app.