Predatory Sliver

Watcher Sliver

All Sliver creatures have "Whenever this creature is dealt damage, put a +1/+1 counter on it." (It must survive the damage to get the counter.)

All Sliver creatures have "{2}: This creature gets +1/+0 until end of turn."

All Slivers have "{T}: Add one mana of any color."

Sliver creatures you control have "{T}: Add one mana of any color."

All Slivers have "{2}, Sacrifice this permanent: Draw a card."

All Sliver creatures have "{2}: This creature gets +0/+1 until end of turn."

Sliver creatures you control have trample. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)

All Sliver creatures have "{2}: This creature gets +1/+1 until end of turn."

Whenever a Sliver becomes blocked, that Sliver gets +1/+1 until end of turn for each creature blocking it.

All Slivers have "Sacrifice this permanent: You gain 3 life."

Sliver creatures you control have menace. (They can't be blocked except by two or more creatures.)

Sliver creatures you control have haste. (They can attack and {T} as soon as they come under your control.)