Thats already a great start, but dont discount that attack trigger either
The majority of expensive cards come from the Japanese 2002 McDonalds Pokmon-e Minimum set
Chart shows the price of Hoopa EX #XY71 at the end of each month going back as long as we have tracked the item.
As far as card recommendations go, Id suggest running the likes of Essence Pulse, Blossoming Bogbeast, and Mortality Spear
Koth of the Hammer Many of the land-animating planeswalkers push you towards playing mono-colored decks, and Koth of the Hammer is no different, encouraging you to play mono-red since every ability references Mountains
BPhillipYork: Dangerous card that will let you really explode with lots of Slivers, especially with things like Gemhide Sliver letting your Slivers generate mana