Not a ton of first basemen on the free agent market for those looking. And not much quality in the lot. The Rangers aren’t looking, seeing as how they have Ronald Guzman, Joey Gallo, and Jurickson Profar.
But for a team so inclined, here is the list. Not one of these players will make much impact. If you don’t have a first basemen in your system better than any of these players, you have a lot more problems than just needing a first baseman.
(Players in bold are former Rangers.)