There are several new card types in play with this set:

Ally is a new creature type. An ally has an effect (getting larger, gaining life, making creature tokens, etc.) that triggers when itself or another Ally enters the battlefield.

Landfall is a new ability that allows a creature, enchantment, artifact, or land to gain an extra ability or become more powerful when a land enters the battlefield under its controller's control.

Quests are enchantments that each have two abilities. The first ability causes "quest counters" to be added when a specific event or game state takes place; once a certain number of quest counters is reached, the card's second ability can be used.

Trap is a new type of instant that can be cast for a reduced cost if certain events have taken place this turn.