World Championship Decks: Since 2004, Pokmon has released replica decks of the World Champions' winning hands
With interesting mechanics, both new and old
Some playgroups or game stores dont like specific cards, either banning them outright or classifying decks with them in a specific category to avoid pubstomping
Three main factors determine value: rarity (Secret Rare, 1st Edition, etc.), condition (graded on a 1-10 scale where PSA 10 is flawless), and demand (popularity of the Pokmon and competitive playability)
Alternatively, you can also try to draw a Radiant Greninja to the field to use its Concealed Cards ability
Lets take a look at a couple 18-land decks to get us started