The card Dragon Egg seems like a slam-dunk inclusion, as does Nesting Dragon if you picked one of those up in last year's Commander decks
Milling refers to putting cards from the deck into the graveyard, so theyre not discarded and dont trigger madness
The only risk is getting your biggest creature removed in response (or getting its power shrunk, but no one plays those effects, right?)
If you havent got a Timelord in your hand, cards such as Time Maiden will allow themselves to be banished in exchange for a fetched Timelord in your deck
Whereas, large playing cards are better for visibility and accessibility
The Attribute Knights are just there to make Black Luster Soldier - Envoy of the Beginning easier to access although there is a nice combo with an empty hand, Armageddon Knight, Swift Gaia the Fierce Knight and The Warrior Returning Alive where you summon Armageddon Knight, send Gaia then using The Warrior Returning Alive to then summon Gaia from your empty hand, not reliable by any means but a fun combo nonetheless