Assuming you don't want something like the Double Alpha Race holster or the like. These are more "holders" than holsters.
I use the Comp-Tac 6" for L Frame holster for my 686 when shooting ICORE Classic.
I also have one for 6" N frame model for the 929 to use in ICORE Limited and USPSA.
Oh, heck, I'm prejudice. Pretty much use Comp-Tac for all competition holsters. Then I'm not a master shooter or a speed demon on the draw.