Provide race-like bonuses, but only apply for one turn/round and are cheaper. Be best to have a limit for cards similar to limit on boosts- 1 to 5 free ones+store ones, based on map size, and divided into offensive, defensive, and miscellaneous card. For each section there is a standard deck from which the free cards come from and then store-only cards.
List of cards:
Offensive
Standard Deck
- +5% attack (max 3 free per game)
- +10% attack (max 1 free per game)
- Attack boost is not consumed if first roll wins (max 1 free per game)
Store Only
- +5% attack with attack boost
- +10% attack with attack boost
- +5% attack with defense boost
- +10% attack with defense boost
Defensive
Standard Deck
- +5% defense (max 3 free per game)
- +10% defense (max 1 free per game)
- Defense boost is not consumed if attacked with attack boost (max 1 free per game)
Store Only
- +5% defense with attack boost
- +10% defense with attack boost
- +5% defense with defense boost
- +10% defense with defense boost
Miscellaneous
Standard Deck
- +5% spawn (max 3 free per game)
- +10% spawn (max 1 free per game)
- Add together two largest "blobs" for spawn amount rather than just largest (max 1 free per game)
Store Only
- -5% spawn to all enemies
- -10% spawn to all enemies
- +5 storage (lasts all game, can only be used once per game)
- Fortify troops
Suggest any other ideas, give comments, or ask questions below.