Ive had it make me a few iphone apps to sideload, a crossplatform manga reader with the goal supporting all backups/extensions/repos and having every paid feature all those apps have, it works suprisingly well, even implemented internet archive as an extension. Haven't tested anything other than mihon, komga, and suwayomi support but that works well. Mostly just get stuck in a loop testing and tweaking the ui for hours.

Also an rss reader with hidden/pinned categories and the ability to rearrange feeds, multiple pane views with the ability to dynamically rearrange the layout on the fly, I fking love it, I couldnt find any that let you hide categories which led to me having it make an extension for freshrss, eventually just turned into making an app. It fits all my needs for an rss reader and is seemingly stable.

Couple blender extensions too, they dont create anything, just speed up my workflow by adding options that used to require workarounds.