I included three counters that counter target spell and bounce something at the same time quite ably - Lost in the Mist, Cryptic Command, and Very Cryptic Command
With the right cards being exiled, Rex, Cyber-Hound can gain a plethora of strong effects on itself
[+1]: Until your next turn, up to one target noncreature artifact becomes an artifact creature with power and toughness each equal to its converted mana cost
Decks built around sacrificing creatures are sometimes known as Aristocrats decks due to cards like Falkenrath Aristocrat and Vampire Aristocrat which have sacrifice effects that power them up
Trading Post ensures you can turn those stolen artifacts straight into card draw
This legendary yeti naturally strengthens his offense for a minimal mana investment, so defensive measures will be your primary concern once he arrives to the battlefield