I have no idea if this is the case, but the Final Fantasy set feels powerful, and it may have been reshaped to fit into Standard
Stealing your opponents Ragavan at instant speed can be monumentally powerful, but giving players the option to also outright counter a spell or draw two cards if the need arises makes this an astoundingly powerful spell
The artifact lands are very strong, but their potency is debatable, with full playsets being legal in formats like Legacy and Pauper, and Arcbound Ravager doesn't see much play anymore
The gems offer more bang for their buck and can be used to purchase a multitude of cards, generally in bigger quantities
Heliod, Sun-Crowned | Illustration by Lius Lasahido +1/+1 counters are game objects or markers that go onto creatures and increase their power and toughness for as long as though counters remain