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.
IK Multimedia Pick and Mix [desktop]
There is a good desktop deal on right now. Buy one, get X plugins added (depending on how many people buy in - currently 4 free products) [Edit - now 7 free] https://www.ikmultimedia.com/pickandmix/
If you combine it with the Fender Collection 2 offer at JRR (https://www.jrrshop.com/ik-multimedia-amplitube-fender-2) then you can buy in for $65. (Add it to your cart and it will discount it by 50%). You can then register this at IK Multimedia for $149 value and pick the other plugins up to that value free of charge.
The tape emulations are supposed to be the best around if you are into that. It’s a cheap way to buy into T-RackS 5 as well which is 9 plugins in one.