I daresay that if they were legal today and Hedron Crab was in the revisiting of the Zendikar setting (Battle for Zendikar), we would have a mono-blue Mill deck in the meta, and even that would pale in comparison to decks that better utilize the fetches to their fullest extent
The weirdest things occur when you tried to use Gardevoir when it was just out
If you grew up in the 90s or the aughts, theres a good chance you either yourself partook or knew those who did in Yu-Gi-Oh card fights or traded cards with other Pokmon collectors
While this obviously pairs up well in most high-toughness matters decks, such as Doran, the Siege Tower, this card still will be a great curve-topper for almost any green deck with huge creatures and a decent amount of mana ramp
Just play a deck filled with cantrips, and youve got a winning strategy
Since Lightsworns love milling their deck, odds are you'll have Monsters in the Graveyard to guarantee Ryko, Twlightsworn Fighter's effect will go off