Even though cards like Fury or Force of Negation may seem mana-expensive at first glance, these spells are often cast for free, so they don't affect your land count
Central Elevator // Promising Stairs Its hard to ignore a card that says you win the game on it, and Central Elevator // Promising Stairs does that
If those top-tier options weren't enough, Ascended Heroes has plenty of expensive chase cards to hunt, which include Mega Pokemon and partner cards featuring combinations like Lillie and her Clefairy
Storming for just a few cards is going to provide you with some decent creature removal
Pokemon ex evolve from their normal pre-Evolutions, unlike 2012's Pokemon-EX (uppercase), which were always fully evolved Basic Pokemon
Factors like print quality, exclusivity of releases, market recognition , and collector demand all play a role