Chronomaton

{1}, {T}: Put a +1/+1 counter on this creature.

Drillworks Mole

{2}, {T}: Put a +1/+1 counter on this creature and a +1/+1 counter on up to one target commander creature you control.

Steel Overseer

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

Omarthis, Ghostfire Initiate

Omarthis enters with X +1/+1 counters on it.
Whenever you put one or more +1/+1 counters on another colorless creature, you may put a +1/+1 counter on Omarthis.
When Omarthis dies, manifest a number of cards from the top of your library equal to the number of counters on it.