My Winchester 1300 Shadow 12 ga pump turkey gun is basically stock. I have installed TruGlo fiber optic sights, a picatinny rail and a TruGlo red/green dot sight. Turkeys fear it!!
I also have a Mossberg 590-A1 12 ga pump tactical shotgun. It is bone stock at the moment. However it is new and a work in progress! It has a black synthetic stock and matte black barrel and receiver. I have added a sling, a 6 round shell carrier and I plan to add a weapon light and maybe a green laser sight when Barack-O coughs up my tax refund!! Bad guys fear this one.
Standard stock, shotguns should be simple, sling, she'll carrier and a light are enough.
Now adding more crap just because you want to add stuff is fine, but I'm of the opinion that adding lasers, optics, etc... To a HD shotgun has no purpous. Pump action shotguns have been doing the job with nothing aftermarket for a long time.