Megaflora Jungle

Each creature with mana value 2 or less gets +2/+2.
Whenever chaos ensues, create a 1/1 green Insect creature token with flying named Butterfly.

The Western Cloud

Prevent all damage that would be dealt to creatures and planeswalkers you control.
Whenever chaos ensues, create three tapped Treasure tokens. They each deal 1 damage to each creature and each planeswalker.

Isle of Vesuva

Whenever a nontoken creature enters, its controller creates a token that's a copy of that creature.
Whenever chaos ensues, destroy target creature and all other creatures with the same name as that creature.

Velis Vel

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Elemental Shamans and an Elemental Spirit are on the battlefield, each gets +2/+2.)
Whenever chaos ensues, target creature gains all creature types until end of turn.

The Eon Fog

Players skip their untap steps.
Whenever chaos ensues, untap all permanents you control.