Biomancer's Familiar

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.
{T}: The next time target creature adapts this turn, it adapts as though it had no +1/+1 counters on it.

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Sol Ring

Summon: Leviathan

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Return each creature that isn't a Kraken, Leviathan, Merfolk, Octopus, or Serpent to its owner's hand.
II, III — Until end of turn, whenever a Kraken, Leviathan, Merfolk, Octopus, or Serpent attacks, draw a card.
Ward {2}

Arixmethes, Slumbering Isle

Arixmethes enters tapped with five slumber counters on it.
As long as Arixmethes has a slumber counter on it, it's a land. (It's not a creature.)
Whenever you cast a spell, you may remove a slumber counter from Arixmethes.
{T}: Add {G}{U}.

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.

Kenessos, Priest of Thassa

If you would scry a number of cards, scry that many cards plus one instead.
{3}{G/U}: Look at the top card of your library. If it's a Kraken, Leviathan, Octopus, or Serpent creature card, you may put it onto the battlefield. If you don't put the card onto the battlefield, you may put it on the bottom of your library.

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Pit Automaton

Defender
{T}: Add {C}{C}. Spend this mana only to activate abilities.
{2}, {T}: When you next activate an exhaust ability that isn't a mana ability this turn, copy it. You may choose new targets for the copy.