For instance large-scale distributed databases today are basically what the Japanese Fifth Generation Computing project was working on.
Production rules engines today are niche products but you'll find at least one inside any bank. Today's rule engines are dramatically better than what people used in the 1980s when they were fashionable, both in terms of improved versions of the RETE engine and using hash tables to keep track of facts.
AI search is still a thing for semiconductor layout, chess playing (now with Markov Chain Monte Carlo, etc.) SAT solvers have improved dramatically, even more than production rules engines. The "semantic web" didn't take off in the wider community but ideas from the semantic web are a secret weapon used by many organizations to crush their competitors.
If you like Common LISP you'll like Novig's book. The ideas there are good for other kinds of advanced programming such as compiler writing.