Myr Scrapling

Sacrifice this creature: Put a +1/+1 counter on target creature.

Iron Apprentice

This creature enters with a +1/+1 counter on it.
When this creature dies, if it had counters on it, put those counters on target creature you control.

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Ashnod's Altar

Sparring Construct

When this creature dies, put a +1/+1 counter on target creature you control.