Many of Blue's spells can interact or interfere with the opponent's spells as well as with the general flow of the game
You're allowed to shuffle your opening hand back into your deck, draw a fresh seven, and keep all of them
PSA-graded cards are smashing sales records
Your alternative commander is Rendmaw, Creaking Nest, a new scarecrow that pays you off for playing cards with multiple card types
"Delve" means "For each generic mana in this spell's total cost, you may exile a card from your graveyard rather than pay that mana." The delve ability isn't an additional or alternative cost and applies only after the total cost of the spell with delve is determined
Marks (MK) This could take the form of a signature which was added at a later date, but any card with writing, ink marks, pencil marks, or evidence of the impression left from the act of writing will ensure a card gets the MK designation