Myojin of Towering Might in exile (Myojin of Towering Might exiled by Agatha's Soul Cauldron).
All other permanents on the battlefield.
Tekuthal has at least one indestructible counter on it, and at least one +1/+1 counter on it.
Steps
Activate Tekuthal using Myojin of Towering Might's ability by removing an indestructible counter from it, putting six +1/+1 counters on Workhorse, and two +1/+1 counters on any creature you control.
Activate Workhorse three times by removing three +1/+1 counters from it, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Activate Tekuthal by paying ({3} magic symbol) and removing three +1/+1 counters from Workhorse, putting an indestructible counter on it.
Repeat.
Results
Infinite +1/+1 counters.
Infinite colored mana that can only be spent to activate abilities of creatures you control.