Koala Sampler
From the App Store description: “Koala is the ultimate pocket-sized sampler. Record anything with your phone's mic instantly. Use Koala to create beats with those samples, add effects and create a track!
Koala’s super intuitive interface helps you make a tracks in a flash, there is no brake pedal. You can also resample the output of the app back into the output, through the effects, so the sonic possibilities are endless.”
AUv3 multi-output plugin as an in-app purchase - [16/9/2021].
App type: App
App store link: 
Developer: https://www.elf-audio.com/koala/
Developer AB Forum Handle: @elf_audio
Additional Info
Koala Basics tutorial:
SoundTestRoom video:
KING