For those who don't know (https://en.wikipedia.org/wiki/Ontology), an ontologist is someone who specializes in organizing concepts into groups and hierarchies, but also higher-order structures. Taxonomist is a related line of work.
In today's tech scene, people with this skillset seem to most often be tasked with designing and building out structured knowledge graphs. Several of the individuals I know also have experience writing Lisp.
This is a fairly niche category, which is why I'm posting it separately from the recent job threads. Please let me know if you have any leads.
The idea is to concentrate the job post in a single place, so most of these post get killed.