How many links do you want? 
Paizo These guys aren’t miniature producers but they have a big collection in their store from many different manufacturers.
Games Workshop - Go Warhammer - if you want Fantasy figures. (WH40k is science fiction), or they have an extensive Lord of the Rings line which is obviously fantasy too. Careful here however as some of the mini’s are plastics not white metal from these guys.
Avatars of War - Highly detailed figures. The sculptor is ex Game Workshop (see above) so the style is similiar.
Heresy Miniatures some great mini’s here and good people to deal with.
Repaer Mini’s One of the oldest players in the game - literally thousands of mini’s there. They were the official D&D mini producers back in 2nd Ed days.
Privateer Press - again they have two game systems one fantasy, one steampunky. They do some really nice mini’s.
Dark Sword Mini’s - really nice mini’s. They hold official licenses for mini versions of artwork by Jeff Easley, & Larry Elmore, amongst others (famous for iconic D&D style artwork for those not in the know). They also have a license for mini’s derived from George RR Martin’s Fire & Ice novels.
Black Orc Games - never ordered form these blokes but they have a large range.
Crocodile Games - big range focused on various egyptian & similiar warband factions, but they have quite a bit outside that range as well.
Wyrd Miniatures Not necessarily D&D fantasy style but a lot of general fantasy style mini’s, various beasties, etc.
That’s a few of the major mini manufacturers. I’ve got links to a lot more small producers who are probably more a hobby than a business, with only a handful of sculpts each.
Also, if your missus has any interest in painting fantasy football mini’s (Orcs, Trolls etc playing stylised Gridiron), I can post up some links to excellent manufacturers of those sort of mini’s.