I've been working on an update to my flashcards app for over a year and half now and I'm finally nearing completion. This is for Mac and iOS only and the app uses Core Data with CloudKit for syncing its data, which has been interesting learning the ins and outs of. (For instance, CloudKit can throttle your sync if you have too many objects, so I ended up having to create snapshot objects to carry lots of records in bulk which I then expand in a local SQLite database to get around its limitations.)

The app has a lot of UX details that I've really enjoyed working on. I wrote up some notes about it here: https://www.freshcardsapp.com/3/

Separately, also working on a Zettelkasten notes app that pushes you to make small, atomic notes that you can organize in "collections" to provide structure beyond just hyperlinking in the note text: https://understory.ussherpress.com/ This has been a lot of fun iterating on. I started with a Miller Columns UI, like Finder, to visualize the graph of connections between notes, but I found that it was too overwhelming to use, so I scaled back and went with a more Notational Velocity-like quick search bar with note addressing. The app UI mimics a browser because I found that it works really well for something like this. I need to polish it a bit more and want to find people who will give it a beta test to help me iterate on the ideas some more.