The Power of Prolog book
Interpreter for a simple Lisp, written in Prolog (HN)
Ciao - Programming language that builds up from a logic-based simple kernel, and is designed to be extensible and modular.
Database The Prolog Way
Prodog - System Administration in Prolog. (Lobsters)
It's Elementary, Dear Watson: Applying Logic Programming To Convergent System Management Processes
Scryer Prolog - Modern Prolog implementation written mostly in Rust.
chalk - PROLOG-ish interpreter written in Rust, intended eventually for use in the compiler.