You could grab the bulk of your singles from TCGPlayer or Star City Games, then pick up a few impulse buys or sealed boosters at your local store
On average it will give you 10 of them, which is an insane amount of ramp
Its specially made for Commander players
(Until your next turn, those creatures attack each combat if able and attack a player other than you if able.) If, during a player's declare attackers step, a creature that player controls that's been goaded is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under that player's control continuously since the turn began (and doesn't have haste), then it doesn't attack
This includes both the regular boosters, and the more expensive Mythic boosters
Sword of Fire and Ice would also perform very well in this deck as you can reliably connect with it and thus have it act as removal