Once per turn: You can Fusion Summon 1 Fusion Monster from your Extra Deck, using monsters you control as Fusion Materials, including this card
While some can contain incredible hits that are worth far more than the purchase price, many are filled with less desirable cards that don't add up to what you paid
The reliability, mana upside, and card draw upside make Herd Heirloom a great card for green creature decks
Milan Christopher provides resources where Whitton Greene provides cards, and Amnesia attacks the cards in your hand while Paranoia attacks the resources in your pool
the thing that actually hurts us most is if people destroy our mana rocks as our deck is mana-hungry, so going after our ramp can set us back multiple turns
Ultimately the Pokmon Company are just trying to provide collectors and players with something new to keep them coming back