SLIME is the Superior Lisp Interaction Mode for Emacs. It has support for interacting with a running Common Lisp process for compilation, debugging, documentation lookup, and so on.
Portacle is a portable and multiplatform Common Lisp environment. It ships Emacs25, SBCL, Quicklisp, Slime and Git.
Using Emacs as an IDE
Setting up Emacs on Windows or Mac
Slimv is a full-blown environment for Common Lisp inside of Vim.
Vlime is a Common Lisp dev environment for Vim (and Neovim), similar to SLIME for Emacs and SLIMV for Vim.
See Atom-Slime. This package allows you to interactively develop Common Lisp code, helping turn Atom into a full-featured Lisp IDE.
For reviews of plugins for more editors, including free versions of proprietary ones (LispWorks, Allegro), see Articulate Common Lisp.