Ratadrabik of Urborg | Saw in Half | Mondrak, Glory Dominus

(and one other card)

Cast
Saw in Half by paying ({2} magic symbol) ({B} magic symbol) , destroying
Mondrak and creating four token copies of it with base power equal to half the destroyed creature's power and base toughness equal to half the destroyed creature's toughness, rounding up each time.
Put all but one
Mondrak token into your graveyard due to the legend rule.
Ratadrabik triggers four times from the nontoken and token
Mondraks dying.
Resolve the first trigger, creating 2^X nonlegendary token copies of
Mondrak that are 2/2 Zombies, where X is the number of
Mondraks you control plus one.
Repeat step 4 for the remaining triggers.

Assuming you control no other token doublers, this combo will make a total of 10^(10^308.0343553279263) creature tokens.