Introducing mine, a Coalton and Common Lisp IDE

It's good. Easy to install, easy to use, although it lacks colors here and there to better see REPL output. It has essential features (compile function, file, project, interactive debugger with restarts, REPL, go to definition…) and IDE-like ones (create project, build executable button, files side tree…) but hey, it's an otherwise minimalist brand new editor. Of course Slime (or Lem) have more CL-related features, as of today at least (restart a frame, call-defun, cross-references, more REPL shortcuts, more hints in the menus…).

For newcomers, I also advise to look at ICL, it's a terminal REPL with nice features. Also easy to install. This isn't an editor but you can still (load "…") the file you write from the outside.

all editors: https://lispcookbook.github.io/cl-cookbook/editor-support.html (with new additions such as a Zed plugin (requires heavy compilation), an up-to-date (supposedly) Intellij plugin etc)