Godot is what I use. Godot is free, open source, small, and fast, and it's great for quickly and easily prototyping and building a game because of its solid features and scene tree component structure. It's also very fast and easy to export builds for different platforms. More games are being made in Godot every year. That said, it does have some weaknesses. It's not as good at photo-realistic 3d rendering, so if you want to make an "unreal" looking 3d game, you'll want to go with Unreal Engine. Another complaint that I've heard is that, due to how it's designed to use the clean, fast scene tree component structure rather than lots of imported global classes, it can take some getting used to, especially when working with multiple programmers on one project. Another argument that people have used is that the Unity dev community is huge, while the Godot community is small and it's hard to find help, but that's simply not the case anymore. Between the documentation, YouTube, Reddit, and Discord, I've had no problem finding help. If you're freelancing, then Godot is a no-brainer. You'll get a lot more done is less time, and you'll never have to worry about being forced to pay royalties or fees.

@Ben Biedrawa The workflow in Godot is much faster than in Unity for most things, plus, because of the clean node system of Godot, your project is way more organized and cohesive by default, which makes things easier later in development. For example, Godot's nodes can each only have one user created script attached, and each script can only extend one class. The nodes can be arranged in a tree structure, and click together like Lego to form larger components. It not only makes building things in Godot easy to do, but the result is easy to read, allowing future you to tell what's going on. In Unity, there aren't really the same guiding restrictions, which tends to result in chaos and confusion unless you're really careful and disciplined.

Super Mario Bros Wonder is actually really fun. I've been playing it a lot lately. It's a great game if you want to experience some fun surprises and top tier level design. Before that, it was Hades... mostly for the writing. I learned a lot about combining a very grindy game-loop with character writing and storytelling, all without making the player feel interrupted.

I'm Jonathan (aka Dr. Bamboo) My game development has been taken over by cats! Between my main project, "A Meowgical Journey", and the jam project about tiny cats breaking into the castle in pursuit of catnip. I'm a game dev, composer, and writer. I'll share more when the time is right. In the meanwhile, you can check out my stuff at: https://linktr.ee/dr_bamboo