Thopter Squadron in exile (exiled by Agatha's Soul Cauldron).
All other permanents on the battlefield.
Wildwood Mentor has at least one +1/+1 counter on it.
({1} magic symbol) available.
Steps
Activate Wildwood Mentor using Thopter Squadron's first ability by paying ({1} magic symbol) and removing a +1/+1 counter from it, creating a 1/1 Thopter artifact creature token.
When the Thopter enters the battlefield, Wildwood Mentor's first ability triggers, putting a +1/+1 counter on itself.
Activate Krark-Clan Ironworks by sacrificing the Thopter, adding ({C} magic symbol) ({C} magic symbol) .
Repeat.
Once you have infinite mana, you may forego sacrificing the Thopters.
Once you have infinite creature tokens, you may activate Wildwood Mentor using Thopter Squadron's last ability any number of times.