I was in the exact same situation. I know Rust but don't want to use it for everything... had a look at: Zig - attempts to stay simple, like C, but with warts

I was in the exact same situation. I know Rust but don't want to use it for everything... had a look at: Zig - attempts to stay simple, like C, but with warts fixed and with cool compile-time programming. Its biggest strength seems to be not the language itself, but the compiler and build system which can cross-compile seamlessly, including C code. Nim - a systems-language that looks like Python and tries to be fun to write. Has macros that may remind you of Lisp macros. Compiles to C or JS. D - older but very cool as well... I was surprised to find out its metaprogramming capabilities are as good as Zig's or Nim, and that is has a lot of cool features not seen in mainstream languages, like contract programming and executable documentation. Much more mature than the previous ones. Also seamlessly compiles and imports C. Odin - really reminds me of Go. It's used in production to create fluid simulation for Holywood movies apparently. Very minimalistic language but I couldn't see what it brings to the table that the ones above do not. It's kind of similar also to Jai which is also upcoming but focusing on game programming from what I understand... that's still not even publicly available yet. Which one to choose really depends on your taste, hope my descriptions above help, even if they're pretty rough simplifications. If you want the most popular language in this area, that's undoubtedly Rust though.