As of the Smash Up Goblins expansion, there are 83 factions, which can combine to form 3,403 unique pairs of factions.[1]
Each player shuffles two factions together to form their deck of 40 cards. Every faction typically has 20 cards with some combination of minion cards and action cards. Factions have a typical structure, although there are many exceptions. The typical structure of a faction's cards is the following:
Each faction has special gameplay mechanics common among the faction's minions and actions that connect with their theme. For example, Zombies come back from the discard pile, Mad Scientists generate and spend +1 power counters, and Ghosts gain bonuses when having only a few cards in their hand.
Each faction releases alongside two bases associated with their theme (except Polynesian Voyagers who have three). Depending on how you build the base deck, bases associated with factions that weren't chosen to play may still appear, and bases associated with chosen factions may appear more or less often. Bases typically favor the gameplay of their associated faction, though there are many examples where this is debatable or in theme only: Tar Pits (the Dinosaurs have no more advantage than others who can't revive minions), Cave of Shinies (the Tricksters are better at destroying other players' minions than their own, and their minions already punish those who destroy them), The Dread Gazebo (the Ghosts get no advantage from it and they even have a play-on-base action), neither of Elder Things' bases favor them, Q Point (symbolizes a point of conflict for the Magical Girls but only sometimes favors them), etc.
Play many powerful actions that penalize you with Madness cards, and recover cards from the discard pile, often at the cost of destroying your own minions.
Copy other players' power and abilities, boost your minions' power, and destroy and replace your minions with other minions, especially from your deck.
Sort your deck, take a peek and manipulate the top of each player's deck, force your opponents to discard cards, and play specials while bases are scoring.
Weaken other players' minions, temporarily take control of weak minions, and destroy your own minions for effects, whether minions you played or minions you took control of.
Play with a reduced number of minions in your deck, but with a cast of six power-5 minions with useful abilities, and support your deck with movement, card draw and minion retrieval.
Draw treasures, gain benefits for having treasures in hand, usually discarding them for the benefits, and steal things from other players, such as cards or VPs.
Play and destroy monsters on bases to manipulate their breakpoints and gain treasures, and gain power boosts from the presence or the destruction of monsters.
Play play-on-minion actions, use talents to switch your minions between a powerful form and a weaker form with a useful ability, and move your minions around.
Return your minions to hand for benefits, and manipulate how your minions are affected, like moving them instead of returning them or having your power-2 minions be affected instead of others.
Play low-power minions as extras, gain benefits from the presence of other players' minions on their bases, and play actions that neutralize strong opposing minions.
Play with fewer minions than normal, but gain power through your play-on-base actions, destroy other players' cards, manipulate bases and summon a giant freaking titan.
Transfer play-on-base actions around in order to move your minions, and mess with other players' play-on-base actions, either by transferring them elsewhere or taking control of them.
Play with a reduced number of minions in your deck, but with a team of seven power-4 minions with powerful and oppressive abilities, including hard removal, power boost and retaliation.
Draw and retrieve cards from your deck and discard pile to get your best cards out as soon as possible and keep them around for as long as possible. (Previously found in the All Stars Event Kit)
Search for and play actions on other players' minions, especially Set-Up actions, as a requirement to activate or play cards with much greater effects.
Give cards to other players for benefit, gain benefits when they play or discard them, and give away actions that are continuously passed between players.
Play with a reduced number of characters in your deck, but with a cast of six power-5 characters with useful abilities, and each associated with a unique action that has two abilities, a regular one and a stronger one when the right character is in play.
Play with a reduced number of minions in your deck, but with a team of seven strong minions, move them around, and have them end their movement on a base with your play-on-base actions to trigger various benefits.
