Leather Pancake.

There are subtle differences in rake and height. But they are much more critical for concealing a 4in revolver or full size semi under a shirt tail, than fo for a.2-2.5in. Frankly it's hard to mess up the basic design badly enough to be unsuitable for a snub.

But for the obligatory name check, Roy Baker, El Paso Sadle, DeSantis, Bianchi, for most frequent personal use with snub revolver.