Steel Overseer

{T}: Put a +1/+1 counter on each artifact creature you control.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Stone Idol Generator

Whenever a creature you control attacks, you get {E} (an energy counter).
{T}, Pay six {E}: Create a 6/12 colorless Construct artifact creature token with trample. Activate only as a sorcery.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Cayth, Famed Mechanist

Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Other nontoken creatures you control have fabricate 1.
{2}, {T}: Choose one —
• Populate.
• Proliferate.