The most important factors are edition (1st Edition, Shadowless, Unlimited), condition (mint cards command premiums), rarity (holographic, secret rare, full art), age (vintage Base Set cards are highly sought after), and the Pokemon itself (Charizard, Pikachu, and fan favorites are worth more)
Magmar (Fossil) Strange proportions and an awkward, hunched pose plague this Fire-type Basic Pokmon card
USGMENs glorious shiny Mew artwork, is one of the most exciting sets from the upcoming Paldean Fates set
Your decks need to be able to do those things. Based on the bolded sections here, the play experience they are looking to cultivate is wildly different from my own ideal game
Using your Leader effect to give your opponent 1000 attack every turn, you can solidify your defenses and build up for a sturdy endgame even with a mono-red deck
#5: Rest in Peace Power : 5 Speed : 2 Splashability: 1 Rest in Peace is usually a game-ender against decks that live and die by the graveyard