quite extensive (somewhat outdated) overview » http://www.ntlug.org/~cbbrowne/lisposes.html

Mezzano is an operating system implemented in ANSI Common Lisp running on x86-64 and arm64 based systems. It is far more complete than Movitz and still under active development. It has multiprocessing, support for networking and several file systems, including a custom local world-based based one, FAT32, ext2/3/4, and remote filesystems.

Movitz is (was?) a dev. platform for LISP like OSes, currently with a kernel, Cross Compiler for x86 based metal. “The Movitz system aspires to be an implementation of ANSI Common Lisp that targets the ubiquitous x86 PC architecture 'on the metal'. That is, running without any operating system or other form of software environment. Movitz is a development platform for operating system kernels, embedded, and single-purpose applications.”

see: Lisp Machine