This is my deep sea series as support cards for Commander.
Hydrothermal Vent Field
Land
T: Add C.
T: Regenerate target Kraken, Leviathan, Octopus or Serpent.
Cold Seeps
Land
Kraken, Leviathan, Octopus or Serpent spells cost 1 less to cast.
T: Add C.
Deep-Sea Trench
Land
T: Add U.
UU, T: Target Kraken, Leviathan, Octopus or Serpent gains Hexproof until end of turn.
Vent Worm
1UU
0/1
Creature - Worm
Activate each effect of Vent Worm only once.
T: Create a 1/1 Blue Crab creature token.
T: Create a 2/2 Blue Fish Creature token.
T: Sacrifice a Worm, Fish and Crab creature: Search your Library for three Kraken, Leviathan, Octopus or Serpent creature cards and put them into play. Then shuffle.
Microbial Spire
U
0/1
Creature - Ooze Wall
Defender
Sacrifice Microbial Spire: Search your library for a Kraken, Leviathan, Octopus or Serpent card and place that card on top of it.
Olantin, Lost City
Legendary Land
T: Add U
2, T: Add U equal to your devotion to Blue. Use this mana only to cast Blue creature spells.
Thassa's Secret Abyss
Legendary Enchantment
3UU
During each player's upkeep, apply one of the following effects:
* Create a 0/1 Blue Worm creature token
* Create a 1/1 Blue Crab creature token.
* Create a 2/2 Blue Fish creature token.
At the beginning of your upkeep, you may sacrifice a Crab, Worm and Fish Creature: Search your library for a Kraken, Leviathan, Octopus or Serpent creature and put it into play. Then shuffle.
Hydrothermal Vent Field - Looks fineish. Most effects like this the land produces colorless. This is a little pushed but most likely okay since it's the worst creature types.
Cold Seeps - This also feels like it should produce colorless. Otherwise there is almost no cost to running it. It's effectively a better Eldrazi Temple.
Deep-Sea Trench - Same issue as all the above. The cost on the second ability needs blue in the cost. Probably double blue.
Vent Worm - Even at it's low power level it still should cost more. A 1 drop that effective can put 3 power on the board if not more.... Not reasonable. Should cost 3.
Microbial Spire - This feels like it's actually correct.
Olantin, Lost City - This also feels correct... Ish. It's like the Devotion land but limited so can make colored Mana. Kinda okay.
Thassa's Secret Abyss - I feel like it should cost 1 or 2 more mana. It's very powerful in just being able to put 2/2s into play every upkeep. The last effect needs some kind of limiting factor. Only during your upkeep or something of that nature. In response to you pushing my fish I'll put a Simic Sky Swallower into play. Feels bad.
Hydrothermal Vent Field - Looks fineish. Most effects like this the land produces colorless. This is a little pushed but most likely okay since it's the worst creature types.
Cold Seeps - This also feels like it should produce colorless. Otherwise there is almost no cost to running it. It's effectively a better Eldrazi Temple.
Deep-Sea Trench - Same issue as all the above. The cost on the second ability needs blue in the cost. Probably double blue.
Vent Worm - Even at it's low power level it still should cost more. A 1 drop that effective can put 3 power on the board if not more.... Not reasonable. Should cost 3.
Microbial Spire - This feels like it's actually correct.
Olantin, Lost City - This also feels correct... Ish. It's like the Devotion land but limited so can make colored Mana. Kinda okay.
Thassa's Secret Abyss - I feel like it should cost 1 or 2 more mana. It's very powerful in just being able to put 2/2s into play every upkeep. The last effect needs some kind of limiting factor. Only during your upkeep or something of that nature. In response to you pushing my fish I'll put a Simic Sky Swallower into play. Feels bad.
I agree with you on all these suggestions and will edit the cards based on them.
Also wanted to add some flying protection for sea monster decks with this thematic card, title from the DND Theros book:
Thassa's Tidelock Pearls
Legendary Enchantment
UU2
Tap a blue creature you control: Tap target creature with flying.
As long as your devotion to Blue is 5 or more: The first Kraken, Leviathan, Octopus or Serpent spell you cast each turn has Convoke.
Cetuseus, the Shelled
UG2
Legendary Creature - Octopus
*/*
Cetesus gets +1/+1 for each Island you control. If Cetesus's power is 5 or more, it has Trample.
Whenever Cetesus deals combat damage to a player, reveal that many cards at the top of your library. You may cast a Kraken, Leviathan, Octopus or Serpent spell from among them without paying its mana value. Put the revealed cards on the bottom of the owner's library in a random order. Ever since the sea gave birth to Cetesus, who earned Thassa's favor sinking a fleet of enemy ships, Thassa declared no other Octopus was worthy of a shell.
Hydrothermal Vent Field
Land
T: Add C.
T: Regenerate target Kraken, Leviathan, Octopus or Serpent.
Cold Seeps
Land
Kraken, Leviathan, Octopus or Serpent spells cost 1 less to cast.
T: Add C.
Deep-Sea Trench
Land
T: Add U.
UU, T: Target Kraken, Leviathan, Octopus or Serpent gains Hexproof until end of turn.
Vent Worm
1UU
0/1
Creature - Worm
Activate each effect of Vent Worm only once.
T: Create a 1/1 Blue Crab creature token.
T: Create a 2/2 Blue Fish Creature token.
T: Sacrifice a Worm, Fish and Crab creature: Search your Library for three Kraken, Leviathan, Octopus or Serpent creature cards and put them into play. Then shuffle.
Microbial Spire
U
0/1
Creature - Ooze Wall
Defender
Sacrifice Microbial Spire: Search your library for a Kraken, Leviathan, Octopus or Serpent card and place that card on top of it.
Olantin, Lost City
Legendary Land
T: Add U
2, T: Add U equal to your devotion to Blue. Use this mana only to cast Blue creature spells.
Thassa's Secret Abyss
Legendary Enchantment
3UU
During each player's upkeep, apply one of the following effects:
* Create a 0/1 Blue Worm creature token
* Create a 1/1 Blue Crab creature token.
* Create a 2/2 Blue Fish creature token.
At the beginning of your upkeep, you may sacrifice a Crab, Worm and Fish Creature: Search your library for a Kraken, Leviathan, Octopus or Serpent creature and put it into play. Then shuffle.
|| UW Jace, Vyn's Prodigy UW || UG Kenessos, Priest of Thassa (feat. Arixmethes) UG ||
Cards I still want to see created:
|| Olantin, Lost City || Pavios and Thanasis || Choryu ||
Cold Seeps - This also feels like it should produce colorless. Otherwise there is almost no cost to running it. It's effectively a better Eldrazi Temple.
Deep-Sea Trench - Same issue as all the above. The cost on the second ability needs blue in the cost. Probably double blue.
Vent Worm - Even at it's low power level it still should cost more. A 1 drop that effective can put 3 power on the board if not more.... Not reasonable. Should cost 3.
Microbial Spire - This feels like it's actually correct.
Olantin, Lost City - This also feels correct... Ish. It's like the Devotion land but limited so can make colored Mana. Kinda okay.
Thassa's Secret Abyss - I feel like it should cost 1 or 2 more mana. It's very powerful in just being able to put 2/2s into play every upkeep. The last effect needs some kind of limiting factor. Only during your upkeep or something of that nature. In response to you pushing my fish I'll put a Simic Sky Swallower into play. Feels bad.
|| UW Jace, Vyn's Prodigy UW || UG Kenessos, Priest of Thassa (feat. Arixmethes) UG ||
Cards I still want to see created:
|| Olantin, Lost City || Pavios and Thanasis || Choryu ||
Thassa's Tidelock Pearls
Legendary Enchantment
UU2
Tap a blue creature you control: Tap target creature with flying.
As long as your devotion to Blue is 5 or more: The first Kraken, Leviathan, Octopus or Serpent spell you cast each turn has Convoke.
Cetuseus, the Shelled
UG2
Legendary Creature - Octopus
*/*
Cetesus gets +1/+1 for each Island you control. If Cetesus's power is 5 or more, it has Trample.
Whenever Cetesus deals combat damage to a player, reveal that many cards at the top of your library. You may cast a Kraken, Leviathan, Octopus or Serpent spell from among them without paying its mana value. Put the revealed cards on the bottom of the owner's library in a random order.
Ever since the sea gave birth to Cetesus, who earned Thassa's favor sinking a fleet of enemy ships, Thassa declared no other Octopus was worthy of a shell.
|| UW Jace, Vyn's Prodigy UW || UG Kenessos, Priest of Thassa (feat. Arixmethes) UG ||
Cards I still want to see created:
|| Olantin, Lost City || Pavios and Thanasis || Choryu ||