Thanks for the information. Right now I only go to the range but I plan on going hunting because my friend is taking me. You guys helped me a lot
Here are my honest recommendations:
Muzzle brakes—Skip. There are more than a few options out there, and none of them really do much to mitigate muzzle rise; this IS a 12 ga after all. Plus, if you care about appearance, the snub snout kind of ruins what makes the KSG special (visually). Save your money.
KNS QD socket/take down pin—If you use a single point QD sling, get it. The fit is nice. It's easy to use and feels more secure than the factory take down pin. It replaces the forward pin. You still need to use the factory rear pin.
Kel-Tec extended butt pad—Get it. It's inexpensive, relatively easy to install and soaks up some recoil.
Kel-Tec choke adapter—If you really must give the KSG a snout, this is probably more useful than any of the muzzle brakes out there. If you want to install this, you'll need the barrel nut removal socket tool and use a impact driver (easy off-on in seconds, no struggling with vise and breaker bars).
Aftermarket alloy magazine followers—Only if you've got money burning in your pocket. The factory followers work fine as they are.
Gear Head Works The Beast—This is a muzzle shroud. If you want to add the choke adapter, but would like to make your KSG look like it didn't grow a snout, this is it. It also adds M-Lok slots and QD points (though I wouldn't make use of them, being so close to the muzzle). You CAN NOT use this with a muzzle brake.
Primary Machine Shell Deflector—If your wrist get beat up by ejecting shells, this is very nice to have. The price is on the high side (85?), but it works and is very easy to install. The factory blem version are $10 less when available. Otherwise, wear long sleeves or use a wrist wrap.
DIY—Check your chamber for smoothness. If it didn't come from the factory smooth, polish it with steel wool wrapped cleaning brush/rod attached to power drill. The cheaper low brass shells can get stuck and fail to extract. Polishing the chamber helps. The rod will allow you to reach the chamber without doing full-on disassembly of your KSG.
Kel-Tec Kydex cheek rest—To me, this is a must have for comfort.
Holosun Paralow 503C—Very good relatively low-cost solar assisted red dot with selectable dot or circle-dot reticle and auto mode (auto brightness and auto on-off). 50k hours of claimed battery life. Build quality is very good. Very close to the Aimpoint T1 and T2 micros to the naked eye. It's meant for ARs, but is perfect on the KSG (so is the circle-dot reticle). Comes with a lower 1/3 co-witness riser and a low profile mounting base. Use the riser. The latter is useless on the KSG.
Magpul AFG/RVG—Take your pick. Either are GTG.