Lore Seeker

Electrolyze deals 2 damage divided as you choose among one or two targets.
Draw a card.

Flying
Whenever you draw a card, Niv-Mizzet, the Firemind deals 1 damage to any target.
{T}: Draw a card.

{3}{B}, Discard a card: Target creature gets -2/-2 until end of turn.
{3}{R}: Create a 2/1 red Goblin creature token with haste. Exile it at the beginning of the next end step.

Counter target spell, activated ability, or triggered ability.

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Assembly-Worker artifact creature token.

You can't cast this spell during your first, second, or third turns of the game.
Flying
Vigilance

First strike, protection from white

Trample, haste
At the beginning of the end step, sacrifice Groundbreaker.

Other Elf creatures you control get +1/+1.
{G}, {T}: Create a 1/1 green Elf Warrior creature token.

Each creature assigns combat damage equal to its toughness rather than its power.

Each other Warrior creature you control enters the battlefield with an additional +1/+1 counter on it.
Each creature you control with a +1/+1 counter on it has trample.

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.