Yule Ooze

At the beginning of your upkeep, destroy another nonland permanent chosen at random, then put a number of +1/+1 counters on Yule Ooze equal to that permanent's converted mana cost.
{R}{G}, Eat some food: Regenerate Yule Ooze.

Revelation

Angel of Jubilation

Flying
Other nonblack creatures you control get +1/+1.
Players can't pay life or sacrifice creatures to cast spells or activate abilities.

Bog Humbugs

Flying
Whenever Bog Humbugs deals combat damage, hum that many notes of a festive song. If you can, put a +1/+1 counter on Bog Humbugs.

Infernal Spawn of Infernal Spawn of Evil

Flying, first strike, trample
Once each turn, while you're searching your library, you may pay {1}{B}, reveal this card from your library and say "I'm coming, too" If you do, this card deals 2 damage to a player of your choice.

Goblin Sleigh Ride

Target creature you control climbs into Goblin Sleigh Ride. You slide them on their merry way. If the creature stayed on, it deals damage equal to its toughness to each other creature touched during the slide.

Selfless Spirit

Flying
Sacrifice this creature: Creatures you control gain indestructible until end of turn.

Sunblast Angel

Flying
When this creature enters, destroy all tapped creatures.

The First Iroan Games

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I — Create a 1/1 white Human Soldier creature token.
II — Put three +1/+1 counters on target creature you control.
III — If you control a creature with power 4 or greater, draw two cards.
IV — Create a Gold token. (It's an artifact with "Sacrifice this token: Add one mana of any color.")

Fruitcake Elemental

Fruitcake Elemental is indestructible.
At the end of your turn, Fruitcake Elemental deals 7 damage to you.
{3}: Target player gains control of Fruitcake Elemental.

Last-Minute Chopping

Ask target opponent if they remembered to get you a present. If they say yes, they put a card they own from outside the game into your hand. Otherwise, you gain control of target permanent they control.

Nice

Search your library for a card and put it into another target player's hand. Then shuffle your library.

Naughty

Search another target player's library for a card and put that card into your hand. Then shuffle that player's library.

Naughty // Nice

Ass Whuppin'

Destroy target silver-bordered or acorn permanent in any game you can see from your seat.

Seasonal Sequels

Pitch the titles of up to X holiday-themed sequels to target spell. Copy that spell for each title pitched, except the copy has that name. You may choose new targets for the copies. (Simply adding numbers isn't festive enough.)

Call to Serve

Enchant nonblack creature
Enchanted creature gets +1/+2, has flying, and is an Angel in addition to its other types.

Kenrith, the Returned King

{R}: All creatures gain trample and haste until end of turn.
{1}{G}: Put a +1/+1 counter on target creature.
{2}{W}: Target player gains 5 life.
{3}{U}: Target player draws a card.
{4}{B}: Put target creature card from a graveyard onto the battlefield under its owner's control.

Chaos Wrap

The owner of target permanent shuffles it into their library. Then they may look at the top card of their library and may wrap it. If it's a permanent card, they may put it onto the battlefield. Otherwise, they may put it onto the battlefield face down as a 4/4 red Present creature. (To wrap a card, put it inside lots of sleeves. If it would be dealt damage or destroyed, remove a sleeve from it instead.)

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Child of Alara

Trample
When Child of Alara dies, destroy all nonland permanents. They can't be regenerated.

Thopter Pie Network

At the beginning of your upkeep, if you're eating, create a 1/1 colorless Thopter artifact creature token with flying. Use food to represent the token.
Whenever a creature token you control dies, if it's represented by food, eat it.

Mishra's Toy Workshop

{T}: Add {C}{C}{C}. Spend this mana only on spells and abilities that put tokens onto the battlefield. Use toys to represent the tokens.

Angel of Mercy

Flying
When this creature enters, you gain 3 life.

Evil Presents

Put a creature card from your hand into play under target opponent's control. That creature attacks each turn if able . . . and always attacks its controller.

Holy Cow

Flash
Flying
When this creature enters, you gain 2 life and scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Infernius Spawnington III, Esq.

Flying, first strike, trample, haste
This spell costs {3} less to cast for each card you've revealed this turn.
When this creature enters, you may say "I'm here." If you do, it deals 3 damage to target player.

Gifts Given

Search target opponent's library for four cards with different names and reveal them. That player chooses two of those cards. Put the chosen cards into the player's graveyard and the rest into your hand. Then that player shuffles their library.

Cradle of Safety

Flash
Enchant creature you control
When this Aura enters, enchanted creature gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)
Enchanted creature gets +1/+1.

Snow Mercy

Whenever a creature deals damage to you, put a globe counter on it.
{T}, {Q}, {T}, {Q}, {T}: Tap all creatures with globe counters on them.

Stocking Tiger

Stocking Tiger enters with a sealed Magic booster pack under it.
When Stocking Tiger deals combat damage to a player, unwrap the booster pack and put it into your hand.

Angel of Glory's Rise

Flying
When this creature enters, exile all Zombies, then return all Human creature cards from your graveyard to the battlefield.

Some Disassembly Required

{B}, Sacrifice a creature: Distribute the sacrificed creature's keyword abilities among any number of other target creatures until end of turn. If it's December, you gain 1 life for each of those keywords.

Season's Beatings

Family gathering — Each creature target player controls deals damage equal to its power to another random creature that player controls.

Marwyn, the Nurturer

Whenever another Elf you control enters, put a +1/+1 counter on Marwyn.
{T}: Add an amount of {G} equal to Marwyn's power.

The Wandering Minstrel

Lands you control enter untapped.
The Minstrel's Ballad — At the beginning of combat on your turn, if you control five or more Towns, create a 2/2 Elemental creature token that's all colors.
{3}{W}{U}{B}{R}{G}: Other creatures you control get +X/+X until end of turn, where X is the number of Towns you control.

An Unearthly Child

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II, III — Reveal cards from the top of your library until you reveal a Doctor card, a card with doctor's companion, or a Vehicle card. Put that card into your hand and the rest on the bottom of your library in a random order.

Eggnogger's 'Stache

Lands you control have "{T}: Refill your mug with a festive drink." (If you don't have a mug, go grab a mug! It's the holidays!)
At the beginning of combat on your turn, if you have a drink 'stache, put two +1/+1 counters on each creature you control.

Greensleeves, Maro-Sorcerer

Protection from planeswalkers and from Wizards
Greensleeves's power and toughness are each equal to the number of lands you control.
Landfall — Whenever a land you control enters, create a 3/3 green Badger creature token.

Fat Ass

This creature gets +2/+2 and has trample as long as you're eating. (Gum isn't food. We checked.)

Infernal Spawn of Evil

Flying, first strike
{1}{B}, Reveal this card from your hand, Say "It's coming": This card deals 1 damage to target opponent or planeswalker. Activate only during your upkeep and only once each turn.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, this creature gets +5/+5 and has flying.

Jenson Carthalion, Druid Exile

Whenever you cast a multicolored spell, scry 1. If that spell was all colors, create a 4/4 white Angel creature token with flying and vigilance.
{5}, {T}: Add {W}{U}{B}{R}{G}.

Liberated Livestock

When this creature dies, create a 1/1 white Cat creature token with lifelink, a 1/1 white Bird creature token with flying, and a 2/4 white Ox creature token. For each of those tokens, you may put an Aura card from your hand and/or graveyard onto the battlefield attached to it.