Niv-Mizzet, the Firemind

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

Island

Mountain

Pyre of the World Tree

Discard a land card: Pyre of the World Tree deals 2 damage to any target.
Whenever you discard a land card, exile the top card of your library. You may play that card this turn.

Invasion of Kaldheim

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Kaldheim enters, exile all cards from your hand, then draw that many cards. Until the end of your next turn, you may play cards exiled this way.

Invasion of Kaldheim // Pyre of the World Tree

Land's Edge

Discard a card: If the discarded card was a land card, Land's Edge deals 2 damage to target player or planeswalker. Any player may activate this ability.

Seismic Assault

Discard a land card: Seismic Assault deals 2 damage to any target.

Niv-Mizzet, Visionary

Flying
You have no maximum hand size.
Whenever a source you control deals noncombat damage to an opponent, you draw that many cards.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.