Ral Partha's first Wererat offering was actually licensed from Citadel in 1982 as part of the "Fantasy Adventurers" line, Fiend Factory 13-2:
They would end up releasing a scant few other Ratmen in the Fiend Factory line over the years:
Heritage, producers of the beloved Knights & Magick wargame in 1980, provided this duo of menacing wererat miniatures as part of their Dungeon Dwellers line: