New kid on the block, Clamiga
With all the new CL implementations recently I'm almost hesitant to write this.
But yet, the project has reached a usable state and it fills a niche, that's mostly what I was after. cl-amiga or Clamiga is a new CL implementation written is pure C (C89/99) and Lisp (gray streams, CLOS). It compiles to a single binary and runs on Amiga retro computers as well as macOS or Linux. On m68k Amigas it has a m68k jit implementation. Well, have a look yourself: https://github.com/mdbergmann/cl-amiga
It runs and passes the test-suites of the most common libraries (I know) like alexandria, bordeaux-threads, serapeum, fset, Sento (of course), Drakma, Hunchentoot, just to name a few. There is a bit of ANSI compliance but not all that much. It has support for ASDF, Quicklisp and Sly/Slynk.