The 686 is an L-frame, Safariland makes their SLS holster in "fine-tac" (kydex) for the 4". I'm not aware of any level 2 nylon ones out there, but there are several leather ones still being made.
Here's one from Stallion Leather S100JR Thoroughbred Revolver Holster Stallion Leather
Blackhawk makes a nice leather pancake, I have one for my 646. It's comfortable and hides well, it tucks in tight with a good belt.