It was, in fact, used on numerous TCGs, such as Jyhad (later Vampire: The Eternal Struggle ) and Netrunner
2000 $150$200 The hype ramps up further
While four of these are exclusive to Collector boosters in the vivid Neon Ink foiling treatment (Aang, Zuko, Katara, and Toph for Air, Fire, Water, and Earthbending respectively), five more neon-less ones can also be found in Play boosters
Cards like these, that let you play as many copies as you want in a deck, are often worth a couple bucks even when printed at common or uncommon
But you can see where they were going with stuff like the Unearth mechanic
Theres a lot of discussion online about the optimal number of turns to pay into Mystic Remoras cumulative upkeep, and the answer really depends on the situation