Kodiak, Magnificent Leader

Partner with Yatar, Always Vigilant (When this creature enters, target player may put Yatar, Always Vigilant into their hand from their library, then shuffle.)
Double strike
Whenever you cast a spell, if it's the first artifact spell you've cast this turn, return target artifact card from your graveyard to your hand. If it's the second artifact spell you've cast this turn, target creature gains +2/0 and first strike until the end of turn.