OR—1 is an artful, generative MIDI sequencer maker. It’s free for iPad as an AUv3, with a desktop macOS version available for €19.99. And it’s an exquisite experience feeding these into synths.
The idea is that you have four lanes, each with its own modes — Euclidean generator, arp, or chord maker. You then have free-running or syncable modulators, set as LFOs or sample & hold, constantly varying those lanes. There’s also a stochastic “flow” control, and plenty of dials to tweak. The result is an endless flow of patterns that ebb and flow. Dial it in or hit random and let it play, or set it up to perform and tweak to your heart’s content.

This is just a MIDI sequencer. Everything is mapped to Western modes and/or chord progressions, with a chromatic option. (The latter could also be mapped to alternative tunings.)
Here I am playing with my own patches for Elastic OSC, plus some brief modified patches from Baby Audio’s BA-1. Dreamy!
In desktop mode, you run as a plug-in (for hosts that support plug-in MIDI output), or run the standalone app and use inter-app MIDI. On the iPad, I used Kymatica AUM. (And it’s also nice to run the iPad as a MIDI source to your computer.)
The AUM setup is simple: add the MIDI Generator as a MIDI channel, then add a synth of your choice:

Desktop for VST3, AU, CLAP, and standalone on macOS.
Free on iPadOS, on the App Store.
https://www.organismi-instruments.com
I’m really looking forward to artist/developer Jori Larres’ forthcoming music release—and this promises to be the first of other software.
Found at The Beat Community; h/t!