They are mostly in Rust language here and on crates.io, but Defold.com and Monogame.net are free and possibly for game consoles later, who knows? Who knows, by the time I finish my next game, Rust may have game console stuff, Steam platforms are already feasible. Rust language runs on about everything with lots of free stuff so why not use it. The current plan is wgpu and egui on top of other things. Those other things would be winit, OpenXR crate, and possibly SDL3. The exact platform specifics may be up for grabs and I may replace SDL3 with winit updates. The platform stuff would be OpenXR for most VR except Apple, SDL3 for non-Mac Apple and Android, and winit for all else. I have verified that Rust now runs on smart TVs like Android TV with compute shaders. There are other minor crates like logging, web-sys, bytemuck, gilrs (bigger), and if I use winit on Apple, a slew of Apple specific crates.
With this I can target all modern platforms, where modern is defined as with compute shaders. I make approximately one game a year and the next game is going to be Paxul 3+, a higher dimensional PacMan game. I might even have multiplayer with things like tungstenite server side and some web sockets stuff built into Rust std probably with tokio. The two I mentioned for game consoles also support similar built in. More on the game: it will include higher dimensional slicing and multiview modes, jiggle the view in numbers of dimensions also. If I need right to left labels, egui with cosmic-text. I will be building a custom higher dimensional tesselletor for the text probably. I may make compute shaders as per minimum any modern GPU framework would allow, or not, who knows? An any dimensional file format is to come too.