These two aspects are key in any game, and Commander really rewards you for it
Theyre in the deck because they smash face super well and have some keywords, thats it
Black Round or Square Corner Shiny Filler Card from Italian Urza's Legacy Foil Common / Uncommon 10 x 11 uncut sheet (Flash to show the shiny/foil on the filler)
To get the best price on specific Pokmon cards, visiting specialist trading card sites such as TCGplayer and Magic Madhouse is often best, as well as checking in your local game store - as they often have their own way of checking a cards authenticity, and rely on their reputation among knowledgeable fans for business
If youre feeling extra daring, you can also double up your triggers with Panharmonicon to perform a decent impression of Krrik, Son of Yawgmoth
The most common bottleneck is the reverse holo section - tracking down the full 153-card reverse holo set in NM condition from individual sellers takes time and patience regardless of budget.