Their value comes from a perfect storm of immense power and extreme scarcity, hailing from a time of tiny print runs
(I always imagine it like being what youd get if chess had certain edge cases where rooks could fly, bishops could teleport, or for a second, pawns were driving tanks.) Since the game is built around several thousand collectible cards, and almost every card has some additional unique ability to it one way or the other, it creates an endlessly manipulable, constantly surprising experience
Gigantamax Inteleon has a very high Attack stat when compared to the current and potential competition, a Gigantamax Move, and a 0.5 second Fast Move to quickly charge up energy if it needs to defend in a pinch
Enchantment - Aura Bard Class (Gain the next level as a sorcery to add its ability.) Legendary creatures you control enter with an additional +1/+1 counter on them
This is easily reds best rare
Kykar beats out Alela narrowly as a vehicle commander just because Jeskai gets you access to more Treasure cards, and Kykar triggers on more card types