The Golden-Gear Colossus

Vigilance, trample
Whenever The Golden-Gear Colossus enters or attacks, transform up to one other target double-faced artifact you control. Create two 1/1 colorless Gnome artifact creature tokens.

Tetzin, Gnome Champion

Whenever Tetzin or another double-faced artifact you control enters, mill three cards. You may put an artifact card from among them into your hand.
Craft with six artifacts {4} ({4}, Exile this artifact, Exile the six from among other permanents you control and/or cards from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Tetzin, Gnome Champion // The Golden-Gear Colossus

Heliod, the Warped Eclipse

You may cast spells as though they had flash.
Spells you cast cost {1} less to cast for each card your opponents have drawn this turn.

Heliod, the Radiant Dawn

When Heliod, the Radiant Dawn enters, return target enchantment card that isn't a God from your graveyard to your hand.
{3}{U/P}: Transform Heliod, the Radiant Dawn. Activate only as a sorcery. ({U/P} can be paid with either {U} or 2 life.)