Spells you cast benefited from the amount of Clerics, Rogues, Warriors, and Wizards on the battlefield or in your party as Wizards of the Coast liked to put it
You have to love the Ents helping the Elves on a Magic card
[65] Unlike the basic Common and Uncommon, Rare collectables are divided into many different sub-groups, comprising Holo Rare, Reverse Holo, Half Art/Half Body, Full Art/Full Body, Secret Rare, Ultra Rare, Rainbow Rare, Promo, and card mechanics including EX/GX, V/VSTAR/VMAX, and Tag Team
A heavily-played meta-defining card that's usually played as a 4-of across multiple formats is likely to have a higher pricetag than a one-off tech card that only sees play in the sideboard of one deck
It really brings in that Green mana element strongly
Exiling the creature is part of paying the encore cost since that rule is written before the colon in the rules text that refers to the mechanic