Would SectorLISP (https://justine.lol/sectorlisp2/) count? It can run the LISP 1.5 metacircular evaluator.

This is pretty small.

http://scheme.dk/blog/2006/12/self-evaluating-evaluator.html

Is Bel a smaller LISP than what's described in The Roots of Lisp? [1]

[1] https://paulgraham.com/rootsoflisp.html

Check Zenlisp and Kilo Lisp under http://t3x.org

Not the smallest, but a great example on how a Lisp can be reimplemented.

Also, http://www.t3x.org/lisp64k/index.html

Boot sector lisp?

https://github.com/jart/sectorlisp