Katerina of Myra's Marvels

As Katerina of Myra's Marvels enters, choose a letter.
Whenever you cast a spell whose name begins with the chosen letter, create a white 2/2 Cat creature token with flying.
Partner (You can have two commanders if they both have partner.)

Park Bleater

Whenever another creature you own enters, you get {TK}.
{W}, {T}: You may put a sticker on a creature you own that entered this turn.

Haberthrasher

Deathtouch
Whenever another creature you control that has a hat enters or a hat sticker is put on a creature you control, each opponent loses 1 life.

Solaflora, Intergalactic Icon

Auras and Equipment you control attached to Solaflora, Intergalactic Icon affect other creatures you control as though those Auras and Equipment were attached to them.
Counters and stickers on Solaflora affect other creatures you control as though those counters and stickers were on them.

"Brims" Barone, Midway Mobster

When "Brims" Barone, Midway Mobster enters, put a +1/+1 counter on each other creature you control that has a hat.
"Brims" Barone, Midway Mobster has menace as long as you're wearing a hat.

Swamp

Hat Trick

Target blocking or blocked creature you control gets +1/+1 and gains first strike until end of turn. If it has a hat, it gains double strike until end of turn. If you and that creature each have a hat, the creature gains triple strike until end of turn.

Main Event Horizon

As an additional cost to cast this spell, choose A through M or N through Z.
Destroy each creature whose name begins with a letter in the chosen range.

Grand Marshal Macie

You may choose not to untap Grand Marshal Macie during your untap step. If you do, put a pause counter on it, then you lose 1 life for each pause counter on it.
Whenever Macie becomes untapped, remove all pause counters from it.
{2}, {T}: Choose an "until end of turn" or "this turn" effect. As long as Macie remains tapped, that effect doesn't end.

Wolf in _____ Clothing

When this creature enters, you may put a name sticker on it. When you do, up to X target creatures each get -1/-1 until end of turn, where X is the number of unique vowels on that sticker. (The vowels are A, E, I, O, U, and Y.)

Knife and Death

Just a second (As long as this spell is on the stack, players can't move permanents.)
One at a time, throw ten cards you own from outside the game onto the playing area from a distance of at least three feet (about one meter). For each of those cards, Knife and Death deals 1 damage to each creature or planeswalker you don't control that card is touching. You gain life equal to the damage dealt this way.

Last Voyage of the _____

When this enchantment enters, you may put a name sticker on it, then it becomes an Aura with enchant creature. Return a creature card from your graveyard to the battlefield and attach this Aura to it.
Enchanted creature gets +2/+0 for each name sticker on this Aura with seven or fewer letters.
When this Aura leaves the battlefield, sacrifice enchanted creature.

A Real Handful

As long as one or more hands are touching A Real Handful, it gets +2/+2.
As long as two or more hands are touching A Real Handful, it has menace.
As long as three or more hands are touching A Real Handful, it has lifelink.

Plains

Rat in the Hat

{T}, Sacrifice Rat in the Hat: Until end of turn, you may cast target creature card that has a hat from your graveyard.

Far Out

Rather than choose the indicated number of modes for spells and abilities you control, you may choose one or more modes. You can't choose any mode more than once.

Scampire

When Scampire enters, you get {TK}, then you may put a sticker on a creature card in your graveyard.
{3}{B}: Return target creature card with a sticker on it from your graveyard to the battlefield. That creature gains haste. Exile it at the beginning of the next end step. Activate only as a sorcery.

Nocturno of Myra's Marvels

As Nocturno of Myra's Marvels enters, choose a word with five or more letters.
Whenever you cast a spell with the chosen word in its rules text, you draw a card and you lose 2 life.
Partner (You can have two commanders if both have partner.)

Form of the Approach of the Second Sun

When this enchantment enters, you gain 7 life. You become a card until you leave your library or that library is shuffled. Put yourself seventh from the top, balancing the cards on top of you on your head.
When you draw yourself, you win the game.
When one or more cards fall off your head, exile them and all cards on your head, then sacrifice this enchantment.

Nearby Planet

Rangeling (This card is every land type, including Plains, Island, Swamp, Mountain, Forest, Desert, Gate, Lair, Locus, and all those Urza's ones.)
Nearby Planet enters tapped.
When Nearby Planet enters, sacrifice it unless you pay {1}.