Master of the Feast Being a big flier is nice for Master of the Feast, but that mana value, though
Hermetic Study/Psionic Gift ( Saga/Legacy/Destiny & Odyssey/Torment/Judgment ) In both sets, these cards served a similar purpose: kill small creatures or allow your smaller creatures to threaten large ones in combat (for instance, Hermetic Study would allow your 2/2 creature to attack into a 3/3 creature with the threat of your third Hermetic Studied creature sweeping away the 3/3 should it block)
Force of Virtue and Sunscour use white cards in your hand and are mana-less ways to have a massive impact on the game
One of the more intriguing cards is Isabela Madrigal (Golden Child), which is fine with a quest of 1 as standard, but her Ladies First ability lets you get +3 lore when questing as long as no other characters have quested that turn
Dee Kay, Finder of the Lost The unique mechanics of Dee Kay, Finder of the Lost warranted a mention