Don't listen to the guy above. Go for the staples first, my priority list= econ>champions vigilance>gravekeeper recruiter>gravekeeper chief>supremacy berry>cocoon of evolution. If you have 3 copies of all of em go for the exclusive card, I go for behemoth just because I like beast type. Aneatereatingant versatile, legacy of yata garasu for spirit mystic box, pikeru can be used for some cheesy comb
I would aim for cards that i can use for farming. Took a foil sword and shield for my labyrinth farming deck. More than half of my deck is now foil which is always good. I would suggest you do the same but that's just me.