Companies that sell 25/28mm Ratmen miniatures.
Note: I have not checked out these sources. Some may produce only science-fiction ratmen (though those can often be converted for fantasy).
Note that even those figures that are out of production may still be available in many hobby shops and online stores.
Alternative Armies: Scottish Napoleonic Ratmen, currently available
Armada: Pirate Ratmen (Pyrats), currently available
DemonBlade: Near-future Ratmen (GothRats), adaptable to fantasy, currently available
Grenadier: Many different Ratmen (Ratscum), including Jezzail and Rat Ogre substitutes, and Archers mounted on Giant Weasels, all sadly out of production
Grim Reaper: A few Ratmen, currently in production
Harlequin: Many different Ratmen (Ver'Men), currently in production
Heartbreaker: Many diffferent Ratmen, all out of production
Inquisition: Many different Ratmen, currently in production
Lance & Laser: Sci-Fi Ratmen (Critter Commandoes), not readily adaptable to fantasy, currently in production
Bob Lippman: Bat-Riding Rats, currently in production
Ral Partha: Several packs of Ratmen (Ratlings), all out of production
Reaper: Many different Ratmen (Verminites), including mounted on Kangaroo Rats, currently in production