Activate another creature you control that has a +1/+1 counter on it by exiling it, creating a 1/1 Human creature token that enters the battlefield with a +1/+1 counter on it due to Metallic Mimic.
Repeat using the Human token instead.

Infinite ETB

Infinite LTB

Agatha's Soul Cauldron

Inquisitive Puppet

Metallic Mimic

Cast Inquisitive Puppet by paying {1}.
When Inquisitive Puppet enters as an Ally due to Maskwood Nexus, it and Haru trigger.
Resolve the Inquisitve Puppet trigger, causing you to scry 1.
Resolve the Haru trigger, earthbending Inquisitive Puppet as it's a land due to Toph.
Activate Inquisitive Puppet by exiling it.
Toph triggers, returning Inquisitve Puppet from exile to the battlefield tapped.
Repeat steps 2 through 4 once.
Resolve the Inquisitive Puppet ability from step 5, creating a 1/1 Soldier creature token.
Repeat from step 5.

Infinite creature tokens

Infinite landfall triggers

Toph, the First Metalbender

Haru, Hidden Talent

Maskwood Nexus

Activate another creature you control that has a +1/+1 counter on it by exiling it, creating a 1/1 Human creature token.
When the Human enters the battlefield, Sigil Captain triggers, putting two +1/+1 counters on it.
Repeat using the Human token instead.

Combos with "Inquisitive Puppet"