This is the build that will carry teams across the finish lines of Act 2 and Act 3. Once the correct cards are assembled, you can kill Ogres, Breakers, and Hags with just two purple frag grenades. Spare grenades will be plentiful across each map, and with two different scavenger skills, you'll be in charge of most of the looting for the team. Propane tanks, flashbangs, and even molotovs can be used to save the team bullets and potentially save them from taking too much damage in otherwise dangerous engagements. Your guns will still be killing most enemies, but grenades can be used on almost every Tallboy variant your team comes across on every map. Pay attention to which corruption cards are active to know what type of grenades to bring. If you don't have enough frags to kill the boss, buy flashbangs to stun them instead. Your teammates can always drop you their frag grenades as well, and you can buy extras from the shop at the start if you need to.
STRENGTHS
You can demolish bosses by spamming frag grenades and if you deploy razor wire, it will be even more effective at stopping commons because it counts as accessory damage. Tallboy variants will all die to just one grenade with a single card or shop upgrade, and you can save the day when the game decides to throw 3 or 4 at you at once. Copper and Offensive Scavenger offer important bonuses to the team while Pyro and Fire in the Hole can add insane value for the cleaners on each map on top of that. Now every propane tank and gas canister can heal you and every grenade you throw is like popping pain meds. The extra copper will let you max out on grenades at the start of every round and even buy a team upgrade from the shop. Running assault rifles/sniper rifles allows you to shoot explosives from a long distance away.
WEAKNESSES
The most dangerous enemies for this build are unexpected common hordes and strangely enough, Stingers. You have high mobility to avoid taking hits from most melee enemies, and you can instantly delete most of the biggest threats in the game, but Stingers will tag you now and then, so be careful to stay near cover or to shoot them quickly. Prioritize taking out Sleepers at a distance to ensure one doesn't accidentally set off on a teammate. Ration your grenade use so you have enough for the entire map.
NOTES
The November patch nerfed Money Grubbers, but it is still the best copper card in the game. Not much else has changed for this build. I am currently experimenting with Overwatch in place of Pyro. The developers have said that they are removing the possibility for boss encounters on early maps in an act in a future patch, but this build can handle them just fine until then.
I personally think running this build with Karlee is the absolute best way of learning the game on Veteran difficulty. You will see all special enemies, all copper spawns, and all grenades, which will simultaneously show you the locations of support items and stash rooms as well. You can rely mostly on using your guns as many people want to do in a first person shooter, and you have a bag of grenades to get you out of trouble if needed. The extra copper gives you extra breathing room for mistakes and even enables bad spending habits because you will have so much of it.
SUGGESTED ALTERNATE CARDS to use until you unlock the ones you are missing
Broadside, Confident Killer, Grenade Training, Overwatch, Marked for Death, Large Caliber Rounds, Lucky Pennies, Share the Wealth, Hazard Pay, Glass Cannon, Shredder, Pep in Your Step, Ridden Slayer, Cross Trainers, Dash, Mad Dash
CHARACTER
Hoffman, Walker, Jim, all provide obvious bonuses that synergize well with the build, but any character can work.
PRIMARY WEAPON
Ranch Rifle is my personal preference, but this build can work with any weapon setup. You can easily change out Tactical Vest in the deck list to suit your own style.
SECONDARY WEAPON
Any, though my preference is a Desert Eagle.
OFFENSIVE ITEM
Frag Grenades or Flashbangs
SUPPORT ITEM
Pain Meds, First Aid Kit
QUICK ITEM
Tool Kit