Mindless Automaton

This creature enters with two +1/+1 counters on it.
{1}, Discard a card: Put a +1/+1 counter on this creature.
Remove two +1/+1 counters from this creature: Draw a card.

Stonecoil Serpent

Reach, trample, protection from multicolored
This creature enters with X +1/+1 counters on it.

Towashi Guide-Bot

When this creature enters, put a +1/+1 counter on target creature you control.
{4}, {T}: Draw a card. This ability costs {1} less to activate for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)

Myriad Construct

Kicker {3}
If this creature was kicked, it enters with a +1/+1 counter on it for each nonbasic land your opponents control.
When this creature becomes the target of a spell, sacrifice it and create a number of 1/1 colorless Construct artifact creature tokens equal to its power.

Monoskelion

This creature enters with a +1/+1 counter on it.
{1}, Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Clockwork Hydra

This creature enters with four +1/+1 counters on it.
Whenever this creature attacks or blocks, remove a +1/+1 counter from it. If you do, it deals 1 damage to any target.
{T}: Put a +1/+1 counter on this creature.

Patchwork Automaton

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever you cast an artifact spell, put a +1/+1 counter on this creature.

Iron League Steed

Haste
Fabricate 1 (When this creature enters, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)

Walking Skyscraper

This spell costs {1} less to cast for each modified creature you control. (Equipment, Auras you control, and counters are modifications.)
Trample
This creature has hexproof as long as it's untapped. (It can't be the target of spells or abilities your opponents control.)

Sparring Construct

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

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.