There might not be many third party lenses for Fujifilm X Mount cameras, but the ones you can get your hands on are top drawer.

The Fujifilm platform is unique: there are very few third-party lenses available for the system. Fujifilm’s reluctance to share the secrets of their AF systems with the like of Sigma, Tamron, and others means that, for the most part, users can only choose from native Fujifilm glass. This is not a bad thing as Fujifilm lenses are fantastic, but many Fujifilm users believe that there are no third-party lenses available at all to use with Fujifilm X Mount cameras.
…
Read full post here:
https://www.thephoblographer.com/2019/08/14/6-spectacular-third-party-lenses-to-use-on-fujifilm-x-mount-cameras/