The Polish crowdfunding exclusive 18 promo cards (only in PL ver.). 10 cards as an add-on (4 Spawn, 3 Loot, 3 Events cards), 8 cards as Stretch Goals (4 Loot, 3 Events, 1 Mission cards):
6 weapons:
Grot assault rifle
Mors wz. 39 submachine gun
Browning wz. 28 light machine gun
VIS wz. 35 semi-automatic pistol
Self-repeating rifle Model 38M
Model 35 antitank rifle
6 events:
Troubled air
Cut-off supplies
Virus
Druggist
Munitions factory
Robbery doesn't pay
4 spawn cards:
Duds [unexploded ordnance]
Sleeping guards
Hunters couple
Fortified post
1 mission - Bounty: Charlie
1 consumable - moonshine
The last 3 events and 1 mission are particularly remarkable as they were inspired by Grumm city, which is not represented in the game.