Staying put: Karl Anderson and Luke Gallows

Where they are currently Employed: The WWE
Why they will likely not change companies in 2019: More money, not a great demand for them in other promotions, friendship with AJ Styles.
Karl Anderson and Luke Gallows were something of a head-scratcher when the WWE hired them in 2016. While they were a member of the Bullet Club stable and held the IWGP heavyweight tag team championships of the world, they were also little known outside of NJPW. Gallows was part of CM Punk's straight edge society stable, but most fans remember him as the Corfed Colossus Festus.
Karl Anderson was completely unknown to WWE fans, but the duo's friendship with AJ Styles led to them being offered contracts. Karl Anderson and Luke Gallows have performed ably and well on the WWE roster, even without being associated with AJ, and the company will likely convince them to stay on in 2019.