Coho is a tool I refer to as "The Kotlin programmer's static website generator." The entire thing is built around the Kotlin scripting engine using a custom Kotlin DSL as a build script.

This makes it significantly more flexible than existing solutions, since you basically get to build your own mini-framework on top of a coho.

Routine is an FTC library I wrote. It was designed as an implementation of WPILib's V3 command library, which uses techniques unsuitable for FTC due to requiring a modern (e.g., non-Android) JVM.

Since Kotlin implements its coroutine model without JVM Project Loom green threads, instead opting for a state machine transformation in the compiler, it can run on an Android JVM, and is thus suitable for FTC use.

godl is another one of those tools born out of frustration of existing solutions. I had been using Godots, but it didn't automatically store version information in the project, so nothing was portable, and it used Godot as the widget toolkit, so it didn't follow the native theme.

To solve this, I learned C++, QML, and the rest of the Qt technologies to make my own project and version manager.

sled is a shader language editor, designed specifically for Minecraft shaderpacks, made using in Godot.

While I still consider it permanently unfinished (who has time for those old projects, am I right), I think it got me curious about IDE and tooling development in general. Since then I've created many more tools and various projects to make my (and other developers') lives easier, but this one in my mind kicked off the whole thing.