Pollenbright Druid
Heres my shortlist of noteworthy upgrade options, divided by price point rather than card function: $1 OR LESS OPTIONS Marionette Master, Armix, Filigree Thrasher, Gravebreaker Lamia, Disciple of the Vault, Voltaic Construct, Ill-Gotten Gains, Stinkweed Imp, Orbs of Warding, Silent Gravestone, Scourge of Nel Toth, Mimic Vat $10 OR LESS OPTIONS Priest of Yawgmoth, Staff of Domination, Crypt of Agadeem, Pili-Pala, Basalt Monolith, Bolass Citadel, Metalwork Colossus, Nettlecyst, Currency Converter, Grim Hireling, Ruthless Technomancer MORE THAN $10 OPTIONS Entomb, Reanimate, Altar of the Brood, Retrofitter Foundry, Cabal Coffers, Defense Grid, Blightsteel Colossus, Darksteel Forge, Revel in Riches, Pitiless Plunderer THEY PUT THE NASTY IN DYNASTY This precon has been one of the hardest to make upgrade recommendations for not because theres any shortage of good options, but because theres just too many equally strong directions to take the deck

Its easy to replace a basic Forest for this card
Read More: Wizards of the Coast Confirms A D20 Should Be Used In Forgotten Realms MTG Dice Mechanic 8 The Book of Exalted Deeds For three mana, you too can have The Book of Exalted Deeds, which is a white mana Legendary Artifact