godot-rust is a GDExtension extension (also available as a GDNative implementation for Godot 3.x) that brings the Rust programming language to the open source Godot game engine.
Rust is a good alternative to GDScript with various tradeoffs for users. While GDScript allows for fast prototyping and short feedback loops, larger-scale games can benefit from a stronger type system, a rich library ecosystem, and native performance.
Rust bindings focus on safety, despite interacting with the engine via FFI. Many APIs are designed to catch errors at compile time, while others offer runtime checks to prevent undefined behavior.
Details and download option are here.