Personally, I'd say my favorite free game engine would be Unity. It's super versatile and user-friendly, making it great for both beginners and experienced developers. Plus, it has a huge community and tons of resources available online, which really helps when you're trying to learn or troubleshoot something. And the fact that it's free to use (with some limitations) is just the cherry on top! But hey, there are plenty of other great options out there too, depending on your needs and preferences.