Counterfeits often have a blue that leans towards purple, navy, or an overly vivid blue
Iconic Pokmon like Charizard, Blastoise, and Pikachu are perennial favorites, and their cards almost always command high prices
Charizard V SR: SA[S9 103/100](Expansion Pack Star Birth) Price: (US$116) The Charizard V card from the Star Birth [S9] expansion has a handful of factors that make it collection-worthy
2) Rockruff Rockruff also has multiple paths to choose from
The card-collecting site Cardboard Connection suggests eBay as your first step, particularly under sold items, as it will tell you how much your cards are worth without having to spend any money (there are also price guide services that are useful)
Cards are only banned in Vintage if they involve the now-defunct "ante rule," use dexterity as a mechanic, or unequivocally impede the flow of tournament play (Shahrazad)