I’ve built a handful of org based iOS apps.

While my initial intention was to bring as much org support to iOS as possible (https://plainorg.com), my thinking evolved over time and I gravitated towards a different kind of mobile-optimised experience, and so https://journelly.com was born. I’ve recently added Markdown support too https://xenodium.com/journelly-1-3-released

I use Journelly the most and is also my most popular app.

I have an org scratch pad and also a habit tracking app https://flathabits.com.

Happy Journelly user here! Finally a great place to store notes/links on my iPhone in a simple but powerful app for rediscovery. That I can bring to my windows / Linux / Mac eMacs.