For IDEs, Shopify provides the Ruby Extension Pack for VS Code [1]. Closely related to RubyMine is the Ruby plugin for IntelliJ IDEA. Those seem to be the biggest set of IDEs for several languages. There's Ruby support for editors like Vim and emacs, but that's a different experience from an IDE.
For those who can Emacs, robe and inf-ruby provide the best developer experience.
Robe runs inside a Ruby process, like Common Lisp's SLIME. This is (far) superior to typical IDEs because it's no longer restricted to static analysis. In a highly dynamic language like Ruby, static analysis can do only so much, so RubyMine and LSP servers have to guess data types. Robe doesn't have to.
Inf-ruby allows interactive evaluation of code, even including redefinition of methods & classes. The items being redefined don't have to be at the top-level, since inf-ruby automatically extracts the surrounding method and class definitions. This means you can just open any source file of your program, edit any method/class that may or may not be deep inside layers of modules & classes, and just ask inf-ruby to send the edited definition to the running Ruby process. Instant code reload.
Of course, it's still Emacs, so sharp corners and rough edges abound. But when it works, it's a boon.
Ye, I noticed trouble with Ruby, RubyMine is the only thing that "works" i.e. provides what I've come to expect out of an IDE for language. Similar experiences for me were Emacs and Clojure or Scala and neovim.
