This can be further strengthened by Gardevoir's previous stage, Kirlia, whose Refinement ability can easily send energy cards into the discard pile
With the highest sale price of $1,500 and only 50 gem mint copies, investing in this card may offer solid returns
Having Solve the Equation in the maindeck strengthens these options as well, and being the sole reason I added one Pact of Negation
For a deeper understanding of what these terms mean, read Timmy, Johnny, and Spike (Mark Rosewater, 2002)
It used to be that Magic let you take an extra turn for as little as two mana, but that turned out to be a little too strong
The low mana curves present in Modern, Legacy, and Vintage make countering a one-drop for free an absurdly powerful proposition