Fission

Fission is a physics engine that I'm currently working on. It was initially designed for my game engine "Fusion", but has since become a standalone project.
I started working on Fission because of my facination with game physics, and because I've used both the PhysX and Jolt physics libraries previously. Initially I was following the Game Physics In One Weekend book series but I've since moved away from following those books (I disagree with parts of them, and the overall approach that the author had).

Currently Fission is very simple, but the GitHub repo does contain some "demos" that you can run if you're interested.

Fusion

Fusion is a game engine that I'm developing during my spare time for the sake of learning more about areas that I'm not familiar with, such as rendering, audio, etc...
It currently supports Windows, and in theory Linux (it's been a while since I've tested it on Linux), but it's not really something I expect people to use.

Hazel

Hazel is a game engine that was initially developed solo by The Cherno (Yan Chernikov) for the purpose of teaching others how you can make game engines. I joined the project on September 11th, 2020 as a volunteer because I wanted to attempt to implement 3D physics, using the PhysX library, and thankfully Yan allowed me to do so.
Eventually I'd go on to work on Hazel C# scripting engine as well as some miscellaneous parts of the engine, but I've always prefered working on the physics side of things.
I was later hired by Yan to work on Hazel professionally.