This spell costs less to cast, where X is the total toughness of creatures you control.
Defender
: Until end of turn, target creature you control gets +1/+0, gains "Whenever this creature deals combat damage to a player, draw cards equal to its toughness," and can attack as though it didn't have defender.

This creature enters with X +1/+1 counters on it.
If damage would be dealt to this creature, prevent that damage and remove that many +1/+1 counters from it.
Whenever a +1/+1 counter is removed from this creature, put two +1/+1 counters on it at the beginning of the next end step.

Compleated ({R/W/P} can be paid with , , or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Until your next turn, up to one target creature attacks a player each combat if able.
+1: Discard a card, then draw a card.
0: Exile target creature or Equipment card with mana value less than Nahiri's loyalty from your graveyard. Create a token that's a copy of it. That token gains haste. Exile it at the beginning of the next end step.

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip (: Attach to target creature you control. Equip only as a sorcery.)

Descend 8 — The Ancient One can't attack or block unless there are eight or more permanent cards in your graveyard.
: Draw a card, then discard a card. When you discard a card this way, target player mills cards equal to its mana value.

You may sacrifice a nontoken white creature rather than pay this spell's mana cost.
Until end of turn, your life total can't change, and permanents you control gain hexproof and indestructible.

During your turn, this spell costs less to cast.
End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Add two mana in any combination of colors.
Draw a card.

Landfall — Whenever a land you control enters, you may have target player lose 3 life. If you do, put three +1/+1 counters on Ob Nixilis.

This creature gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

: Add .
, : Each player draws a card.

Trample
When this creature enters, target opponent creates two 3/3 green Centaur creature tokens with protection from black.

, , Sacrifice this creature: Each player discards their hand, then draws seven cards.

Spree (Choose one or more additional costs.)
+ — Untap all creatures you control. If it's your combat phase, there is an additional combat phase after this phase.
+ — Creatures you control get +1/+0 and gain first strike until end of turn.
+ — Choose target opponent. Whenever a creature you control deals combat damage to that player this turn, create a tapped Treasure token.

: Add .

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Vigilance
You may look at the top card of your library any time.
You may cast Ally spells from the top of your library.
Sacrifice Hakoda: Creatures you control get +0/+5 and gain indestructible until end of turn.

When Terra enters, mill five cards. Put up to one enchantment card milled this way into your hand.
Trance — , : Exile Terra, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.