Myojin of Cryptic Dreams in exile (exiled by Agatha's Soul Cauldron).
Agatha's Soul Cauldron and Mondrak on the battlefield.
Mondrak has at least one indestructible counter on it, and at least one +1/+1 counter on it.
You have an artifact card or a creature card with haste in hand that enters the battlefield untapped and can tap to produce at least ({1} magic symbol) .
You have enough mana to cast the artifact or creature card.
Steps
Cast the artifact spell or creature spell with haste by paying its mana cost.
Holding priority, activate Mondrak using Myojin of Cryptic Dreams' ability by removing an indestructible counter from it, copying the artifact or creature spell three times.
Resolve the three artifact or creature spell copies, creating six token copies of the artifact or creature.
Activate three tokens by tapping them, adding at least ({3} magic symbol) .
Activate Mondrak by paying ({3} magic symbol) and sacrificing two of the tokens, putting an indestructible counter on it.
Repeat from step 2.
Once you have infinite tokens and mana, you may cast any other artifact and/or creature cards in your hand, and use Mondrak to get infinite copies of them.
Results
Infinite copies of each artifact and/or creature card in your hand.