Deranged Hermit

Echo {3}{G}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Deranged Hermit enters, create four 1/1 green Squirrel creature tokens.
Squirrel creatures get +1/+1.

Pandemonium

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

Saproling Burst

Fading 7 (This enchantment enters with seven fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from Saproling Burst: Create a green Saproling creature token. It has "This creature's power and toughness are each equal to the number of fade counters on Saproling Burst."
When Saproling Burst leaves the battlefield, destroy all tokens created with Saproling Burst. They can't be regenerated.

Mana Echoes

Whenever a creature enters, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.