Grusilda, Monster Masher

Combined, enchanted, and equipped creatures you control have menace.
{3}{B}{R}, {T}: Put two target creature cards from graveyards onto the battlefield combined into one creature under your control. (Its power is equal to their total power, its toughness is equal to their total toughness, and it has their names, mana costs, types, text boxes, etc.)

The Legend of Arena

The Legend of Arena can be your commander.
I, II — Create a 2/1 red Human Wizard creature token. Spells you cast this turn cost {1} less to cast for each Wizard you control.
III — Search your library for a planeswalker card, put it onto the battlefield, then shuffle your library. It enters with an additional loyalty counter on it for each Wizard you control.

Spike, Tournament Grinder

({B/P} can be paid with either {B} or 2 life.)
{B/P}{B/P}{B/P}{B/P}: Reveal a card you own from outside the game that has been banned or restricted in a Constructed format and put it into your hand.

Nira, Hellkite Duelist

Flash
Flying, trample, haste
When Nira, Hellkite Duelist enters, the next time you would lose the game this turn, instead draw three cards and your life total becomes 5.

Ol' Buzzbark

When Ol' Buzzbark enters, roll X six-sided dice onto the battlefield from a height of at least X inches. For each die, put a number of +1/+1 counters equal to the result on each creature you control that die is touching. For each die, Ol' Buzzbark deals damage equal to the result to each creature an opponent controls that die is touching.

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)

M'Odo, the Gnarled Oracle

Eminence — {X}, Discard a card: Target player reveals cards from the top of their library until they reveal a creature card with converted mana cost X or less. Put that card onto the battlefield under your control, then that player shuffles the rest into their library. Activate this ability only if M'Odo, the Gnarled Oracle is on the battlefield or in the command zone.

Pippa, Duchess of Dice

{2}{G}, {T}: Roll a six-sided die. It becomes a green Die creature token with power and toughness each equal to its result.
{2}{U}, {T}: Reroll any die. (Activate only any time it makes sense.)

Syr Cadian, Knight Owl

Knightlifelink (Damage dealt by Knights you control also causes you to gain that much life.)
{W}: Syr Cadian gains vigilance until end of turn. Activate only from sunrise to sunset.
{B}: Syr Cadian gains flying until end of turn. Activate only from sunset to sunrise.

Surgeon General Commander

Whenever you augment, enchant, or mutate a creature you control, draw a card.
{T}: Add {W}, {U}, {B}, {R}, or {G}.

Jalum Grifter

{1}{R}, {T}: Shuffle Jalum Grifter and two lands you control face down. Target opponent chooses one of those cards. Turn the cards face up. If they chose Jalum Grifter, sacrifice it. Otherwise, destroy target permanent.

Join the Group

You may put a legendary creature card from your hand into the command zone. It's also your commander.

Champions of Archery

Reach
Commanders you control get +X/+0, where X is the number of commanders you control.

Champions of Archery // Join the Group

Timmy, Power Gamer

{4}: You may put a creature card from your hand onto the battlefield.

Johnny, Combo Player

{4}: Search your library for a card, put that card into your hand, then shuffle.

Stet, Draconic Proofreader

Flying
Whenever Stet attacks, you may exile a card from your graveyard. When you do, Stet deals 4 damage to any target whose name begins with the same letter as the exiled card.
{W}: Delete the first letter of target permanent or player's name until end of turn.

Baron Von Count

Baron Von Count enters with a doom counter on "5."
Whenever you cast a spell with the indicated numeral in its mana cost, text box, power, or toughness, move the doom counter one numeral to the left.
When the doom counter moves from "1," destroy target player and put that doom counter on "5."

Frankie Peanuts

At the beginning of your upkeep, you may ask target player a yes-or-no question. If you do, that player answers the question truthfully and abides by that answer if able until end of turn.

Kharis & The Beholder

Flying
When Kharis & The Beholder enters and at the beginning of your upkeep, create a 1/1 white Human creature token and make a charisma check. (Roll a d20.)
• If the result plus the number of creatures you control is greater than 11, put a +1/+1 counter on each creature you control.
• If the result is a natural 20, for each nonlegendary creature you control, create a token that's a copy of that creature.

Phoebe, Head of S.N.E.A.K.

Phoebe can't be blocked by creatures with flavor text.
{2}{U}{B}: Phoebe permanently steals target creature's text box. (That creature loses all rules text, flavor text, and watermarks. This creature gains them.)

Mary O'Kill

{1}{B/R}: Switch a Killbot or Mary O'Kill in your hand with one on the battlefield. (If a creature is tapped, the switched creature is tapped. The same is true for untapped, attacking, blocking, enchanted, equipped, and targeted. Any counters on a creature are on the switched creature instead.)

The Big Idea

{2}{B/R}{B/R}, {T}: Roll a six-sided die. Create a number of 1/1 red Brainiac creature tokens equal to the result.
Tap three untapped Brainiacs you control: The next time you would roll a six-sided die, instead roll two six-sided dice and use the total of those results.

Acornelia, Fashionable Filcher

Whenever you cast a spell with a squirrel in its art, you get {A} (an acorn counter).
Whenever a Squirrel you control enters or dies, you get {A}.
{2}{B}, Pay X {A}: Target creature gets -X/-X until end of turn.
{G}, Pay X {A}: Target creature gets +X/+X until end of turn.

Alexander Clamilton

Whenever you cast a wordy spell, scry 2. (A spell is wordy if it has four or more lines of rules text.)
{1}{R}, {T}: Choose target creature you don't control. Reveal the top card of your library. Alexander Clamilton gets +X/+0 until end of turn, where X is the number of lines of rules text of the revealed card. Alexander Clamilton fights that creature.

Sol, Advocate Eternal

Legendary partner (You can have two commanders if this is one of them. The other one is promoted to legendary.)
Flying, vigilance
Teamwork — Whenever you attack or block with both Sol, Advocate Eternal and its partner, support 4 and investigate four times.

As long as X is in X's owner's opponent's hand, X's owner may cast X and activate X's abilities. That opponent can't cast X and plays with their hand revealed.
{U}{B}, {T}: Put X into target opponent's hand.
{3}{U}{B}: You may play a land or cast a spell from the hand X is in. If you cast a spell this way, you cast it without paying its mana cost.