Red Ramp: Rituals and Temporary Bursts Green has the greatest amount and variety of ramping cards, but red has its own cards that count as ramp, producing treasure tokens or red mana that disappears by the end of the phase
With that said, when a deck is built optimally, a fetch land could theoretically grant you access to any color of mana desired at the time it's sacrificed
Their main appeal is that they cost less than a quarter each
However, it's also freakishly efficient
More than anything, these moments seem to be self-perpetuating, where everyone gets tremendously excited about one particular card, which creates demand, which raises the price, which exaggerates the rarity, which creates demand The next most expensive right now is the Latias ex at almost $200, then the gold card version of the Pikachu ex at $100, and that Hydreigon pictured above at about $95