Target creature you control deals damage equal to its power to another target creature. If excess damage was dealt this way, discover X, where X is that excess damage. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Whenever you cast a spell from exile or a land you control enters from exile, create a 2/2 green Wolf creature token.
, , Discard a card: Exile the top card of your library. You may play it this turn.

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Double strike
Other creatures you control get +1/+0 for each Aura and Equipment attached to Kellan.

: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on this enchantment.
At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

All Sliver creatures get +2/+0.

, Sacrifice this artifact: Exile target player's graveyard.

Haste
Whenever Captain Lannery Storm attacks, create a Treasure token. (It's an artifact with ", Sacrifice this token: Add one mana of any color.")
Whenever you sacrifice a Treasure, Captain Lannery Storm gets +1/+0 until end of turn.

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
: Add , , or .

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

(: Add .)

If a spell or ability would cause its controller to gain life, that player loses that much life instead.

(: Add .)

(An ongoing scheme remains face up until it's abandoned.)
When you set this scheme in motion, choose an opponent.
Permanents the chosen player controls don't untap during their untap step.
When the chosen player is attacked or becomes the target of a spell or ability, abandon this scheme.

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip

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.

Partner with Regna, the Redeemer (When this creature enters, target player may put Regna into their hand from their library, then shuffle.)
, Sacrifice X creatures: Target player draws X cards and gains X life. Put X +1/+1 counters on Krav.

At the beginning of each combat, creatures you control gain first strike until end of turn if a creature you control has first strike. The same is true for flying, deathtouch, double strike, haste, hexproof, indestructible, lifelink, menace, reach, skulk, trample, and vigilance.

Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Other creatures you control have exalted. (If a creature has multiple instances of exalted, each triggers separately.)