All Sliver creatures get +2/+2.

Whenever a Sliver deals combat damage to a player, its controller may create a 1/1 colorless Sliver creature token.

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

All Sliver creatures have double strike.

Whenever a creature enters, if you cast it from your hand, you may search your library for a creature card with the same total power and toughness, put it onto the battlefield, then shuffle.