Since Bunnelby can attack twice in a turn, it can use Evolution twice, which means that its possible to evolve, say, an Oddish into a Vileplume [Ancient Origins], or Duskull into Dusknoir [Vivid Voltage], depending on which hurts the opponent more
Mega Froslass is one of the newly introduced Mega Pokemon for the Pokemon Z-A game, and as such gets some added hype from collectors looking to bag this Pokemon printed on a card for the first time
Mana Geyser, Treasure makers, and so on can power out monstrous dragons, Eldrazi, an Ugin or two one of the best ways to use excessive ramp is to draw a ton of cards, either to convert that ramp into card advantage, or to ensure you have a bunch of ways to use your temporary mana
Notably, near-mint foils experienced a similar trend
If numbered cards interest you, Serialized Magic Cards, Explained breaks down how the treatment works