[bringtheaction]

Does anyone know a similar library for Rust?

[whyever]

Arb depends on lots of other numerical libraries (namely FLINT, MPFR and GMP or MPIR). If you want pure-Rust alternatives, the ecosystem is just not there yet.

[fdej]

It's a plain C library with an API very similar to GMP, so an option would be to wrap it from Rust, which should not be too difficult.