While the most popular implementation at the moment seems to be egg in Rust, I find that OCaml serves as a much more ergonomic environment for quickly prototyping out uses of egraphs in practice. As a bonus, ego also shares the same logical interface as egg itself, so once you've finalised your designs, you shouldn't have much trouble porting them to egg if you need the performance gains.
While the most popular implementation at the moment seems to be egg in Rust, I find that OCaml serves as a much more ergonomic environment for quickly prototyping out uses of egraphs in practice. As a bonus, ego also shares the same logical interface as egg itself, so once you've finalised your designs, you shouldn't have much trouble porting them to egg if you need the performance gains.