I'd say a few top brands & styles include; Ken Null, Thebeltman.net, 5.11 Tactical, Blackhawk, Galco, Mitch Rosen, Milt Sparks, Tex Shoemaker, Ted Blocker, Greg Kramer(horsehide).
Mitch Rosen(a former Wall St stockbroker) is widely known for gun belts that taper to a thin 1.25" width in front to aid concealment.
TheBeltman site is very popular. 5.11 & Blackhawk sell gun belts with polymer inserts to hold firearms secure.
Clyde