Of course, heavy use of auras can easily be the build for any of these commanders, and theres some overlap on the lists, but I look toward some broader build options here
I particularly love how it basically makes all your Equipment cards into mana rocks, but the really cool part of Urza is its activated ability, which is an improved Temporal Aperture, a nifty old artifact from Urzas Saga
This features new artwork that shows off the progenitor of Innistrad's vampires
For this one, you need seven generic and two blue mana open every turn
You dont really want to answer Sheoldred, the Apocalypse with this, but against a big token or a Voltron commander, this is perfect
This means you need at least three creatures in play to go mana positive