I love my grandma, so it pains me to say this, but Gran-Gran is a pain in the backside
Various cards can add further power to the deck, such as the Goblin Anarchomancer, which makes green and red spells cheaper by one colourless mana, the Mage Slayer, which promises unblockable damage, or the Rhythm of the Wild enchantment, which protects your own creature spells from counterspells
Here's our first take on Urza (note that the young version of Urza would play out as its own card in The Brothers' War ): Urza, Young Artificer (rare) 2WU Legendary Creature Human Artificer 2/4 X, T: Return target artifact card with converted mana cost X from your graveyard to your hand
Quilled Greatwurm Rarity: Mythic Rare TYPE: Creature SUBTYPE: Wurm CMC: 6 Mana cost: USD: $4.78 EUR: 4.81 TIX: 0.02 EDHREC RANK: 2324 (7/7) Trample Whenever a creature you control deals combat damage during your turn, put that many +1/+1 counters on it