I'm sure there are others as well, but Front Rank and Black Cat Bases come to mind. I have some Front Rank swords and Pistols, and find them most satisfactory.
There's also Bronze Age Miniatures. They don't actually have separate weapons in the webstore, but I think David will sell you some if you ask nicely. I know he does pistols, daggers and two types of suitable swords for swashbuckling (though one of these is very thin and bendy).