Krakens 3 in Theros
Leviathans 0 in Theros
Octopuses 1 in Theros
Serpents 1 in Theros but is limited jank
There is also Nimbus Serpent in Gatecrash, simic, but it seems like a card not made for a sea monster deck.
It is a lot cheaper than the 7-drop overload cost for Cyclonic Rift.
Sealock Monster {Octopus} 5-drop 5/5 (8/8 monstrous)
Can only attack while not monstrous if your opponent controls an Island. Once monstrous kicks in you can make a land an island.
Shipbreaker Kraken {Kraken} 6-drop 6/6 (10/10 monstrous)
Kraken of the Straits {Kraken} 7-drop 6/6
Tromokratis {Kraken} "Tromokratis can't be blocked unless all creatures defending player controls block it."
7-drop 8/8
At this point there aren't enough cards to build a deck only with these four creature types in Standard, and a Modern deck would be very, very fat. I wonder if we will get smaller creatures for these types in the coming sets, maybe in the next block. For now, Whelming Wave seems a bit underwhelming, still, I hope we get more Krakens, even a Kraken lord so that we can do like in the movie and shout out "Release the Kraken!"
