15mm Modern Miniature Manufacturers

Quick Reaction Force has the most extensive line of modern miniatures. I use a lot of their figures in my games.

Old Glory makes an increasingly diverse line of 15mm modern minis.

Quality Casting is another manufacturer with a pretty extensive line of 15mm figures. I have a lot of their stuff and it's pretty good.

Peter Pig makes a large line of Postcolonial African and Vietnam 15mm miniatures.