Adventure spells let you cast the Adventure spell or the creature from your hand
Eternal Bargain I don't like what Oloro, Ageless Ascetic did to the format, but you can't deny the power and synergy of this deck, nor how he opened up a lifegain and spending mechanic in Esper
Great for you and a friend
Now if those wildcard bundles are not worth that much to you, I'd understand your hesitation, but within the MTGA economy, this is excellent
Key pieces for a good Grima deck would be Strionic Resonator to double your thievery shenanigans, a good haste enabler through Swiftfoot Boots/Lightning Greaves as well as a way to punish your opponents such as Leyline of the Void or Dauthi Voidwalker
This means that you can respond to the triggers by recasting a spell with flash if it's your turn or casting instants like Brought Back to grab those permanents back to the battlefield