Tiamat

When Tiamat, Queen of Chromatic Dragons enters the battlefield, search your library for up to five Dragon cards with different names and put them into your hand. Then shuffle.
Whenever a Dragon you control attacks, choose one for each color among Tiamat’s heads —
{w}: You gain 3 life.
{u}: Draw a card.
{b}: Each opponent loses 2 life and you gain 2 life.
{r}: Tiamat deals 3 damage to any target.
{g}: Put a +1/+1 counter on each Dragon you control.