Okay well, right away with Felidar Guardian this goes infinite
Elsa also exerts up to 2 characters when entering play, and they dont ready at the start of their owners next turn
However, they can offer great insight into what cards are available to buy in the store once players have saved enough resources
Llanowar Elves would be a nice mana producing creature, but I may use ramp spells like Rampant Growth that add more lands to the field while filling my graveyard as they were one time use spells
Still, adding in sweepers (especially cards like Earthquake and Star of Extinction that take advantage of Sevinne, the Chronoclasm's damage-prevention ability) can greatly improve the deck, and there are some interesting ways to cast cards from our graveyard, like Snapcaster Mage, Mission Briefing and Torrential Gearhulk
Alchemy: Ixalan Lost Caverns of Ixalan