Stumpsquall Hydra

When this creature enters, distribute X +1/+1 counters among it and any number of commanders.

Elder Deep-Fiend

Flash
Emerge {5}{U}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, tap up to four target permanents.

Sphinx of Uthuun

Flying
When this creature enters, reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Avenger of Zendikar

When this creature enters, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land you control enters, you may put a +1/+1 counter on each Plant creature you control.

Scourge of Fleets

When this creature enters, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Meloku the Clouded Mirror

Flying
{1}, Return a land you control to its owner's hand: Create a 1/1 blue Illusion creature token with flying.

Nezahal, Primal Tide

This spell can't be countered.
You have no maximum hand size.
Whenever an opponent casts a noncreature spell, draw a card.
Discard three cards: Exile Nezahal. Return it to the battlefield tapped under its owner's control at the beginning of the next end step.

Trench Behemoth

Return a land you control to its owner's hand: Untap this creature. It gains hexproof until end of turn.
Landfall — Whenever a land you control enters, target creature an opponent controls attacks during its controller's next combat phase if able.

Shipbreaker Kraken

{6}{U}{U}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)
When this creature becomes monstrous, tap up to four target creatures. Those creatures don't untap during their controllers' untap steps for as long as you control this creature.