Using the best cards available will generate the best results, and these staples are the very best
There are some very powerful cards to get from Extradimensional Crisis, like Buzzwole Ex, Pheromosa, Kartana, Luxray, Tapu Koko Ex, Zeraora, Shiinotic, Nihilego, Guzzlord Ex, Silvally, and Celesteela on the Pokemon side, with Repel, Electrical Cord, Gladion, and Lusamine all being decent Supporters or items too
I believe it was Yoni with the pitch that really got me interested: what if these were actual flashbacks in the games
It is a Colorless card illustrated by Kazuhisa Uragami
#1 Mega Charizard X ex SAR The highest raw-to-graded dollar gain on this list at +$327
If you have the standard maximum of 5 Benched Pokemon, thats a not-inconsiderable 150 HP of damage for the cost of just two Colorless Energy