90% Accuracy shotgun lets you snipe weakpoints far away without needing to ADS, you either one shot or stumble mutations with a preferable tac 14
Ammo stash and Heavy hitter lets you deal with common ridden up close/far away but you need to judge when you need it - heavy hitters isn't so useful if your team doesn't let many ridden come close (ie: Melee user is here to deal with most of them)
Money Grubbers + Weapon scavenger helps boost your team by letting you buy upgrades and find higher tier weapons (This build is best used with tac 14 and tech 9 or auto glock)
Buckshot bruiser and Shell carrier both aren't required and can be changed with whatever you prefer, they're just there for extra damage/protection but heavy hitter provides better protection in general imo