Untap all creatures you control and all creatures target opponent controls. You and that opponent each gain control of all creatures the other controls until end of turn. Those creatures gain haste until end of turn.

Changeling (This card is every creature type.)
Whenever an opponent casts a spell, you may put a +1/+1 counter on this creature.

Whenever this creature becomes untapped, you may pay . If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: This creature can't be blocked this turn.

Ward—Pay 3 life.
Whenever you gain life, Amalia Benavides Aguirre explores. Then destroy all other creatures if its power is exactly 20. (To have this creature explore, reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

You may pay rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

When one or more of your opponents are dealt combat damage during your turn, draw two cards. If your library has no cards in it, you win the game. Fblthp's owner shuffles him into their library. (If you draw from an empty library this way, you still win the game.)

Whenever a creature you control attacks, it gets +2/+2 until end of turn.

, Sacrifice a creature: Search your library for a land card with a basic land type, put it onto the battlefield tapped, then shuffle.

, Sacrifice a creature: Discard a card, then draw a card.

Flying
Noncreature spells you cast cost less to cast.

Green creature spells you cast cost less to cast.
Whenever you cast a creature spell, target creature you control gets +2/+2 and gains trample until end of turn.

I. AM. TALKING! — Whenever The Eleventh Doctor deals combat damage to a player, you may exile a card from your hand with a number of time counters on it equal to its mana value. If it doesn't have suspend, it gains suspend.
: Target creature with power 3 or less can't be blocked this turn.

Goblin offering (You may cast this spell any time you could cast an instant by sacrificing a Goblin and paying the difference in mana costs between this and the sacrificed Goblin. Mana cost includes color.)
Whenever Patron of the Akki attacks, creatures you control get +2/+0 until end of turn.

Delirium — Whenever this creature attacks, if there are four or more card types among cards in your graveyard, create a 3/3 green Ooze creature token that's tapped and attacking.

(: Add .)

Whenever this creature or another Zombie you control dies, look at the top card of your library. If it's a Zombie card, you may reveal it and put it into your hand. If you don't put the card into your hand, you may put it into your graveyard.

Discard all the cards in your hand, then draw that many cards.

Whenever a Wolf or Werewolf you control deals combat damage to a player, draw a card.
At the beginning of your upkeep, if you control three or more Wolves and/or Werewolves, it becomes night. Then transform any number of Human Werewolves you control.
Daybound

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

: This creature deals 1 damage to any target and 1 damage to you.