They're one of the original 'tribal' creature types: fish folk has been a viable strategy since the very earliest days of Magic: The Gathering
Historically speaking, this strategy was popular during late 2006, when Cyber-Stein OTK with a Burn transition sidedeck took 1st place SJC San Jose
BT2-054 U Digimon Lv.3 Gotsumon Color Black Cost 3 DP 3000 Digivolve Cost 1 Black 0 from Lv.2 Form Rookie Attribute Data Type Rock Card Text 1 [Effect] Blocker (When an opponent's Digimon attacks, you may suspend this Digimon to force the opponent to attack it instead.) [When Attacking] Lose 2 memory
Again, with any Aristocrat, you'll have infinite life loss, and, with the Altars, you have infinite mana, or can mill your opponents' entire decks
Pokmon 25: The Album launched on October 15th and obviously did not include the pop star V-cards, meaning players will have to hope one of them hawks it online or offers to trade it for, say, a shadowless first-edition holo Charizard
Powerful reprints - Including fan-favorites like Grave Titan and Cryptbreaker