mtg.wtf

Treat your effects that scale off of "players" or "opponents" as though there were one more. (For example, with myriad you'd make an additional token that's just attacking nobody, and with Braids, Arisen Nightmare, you'd draw an additional card.)

Trample
The Mycotyrant's power and toughness are each equal to the number of creatures you control that are Fungi and/or Saprolings.
At the beginning of your end step, create X 1/1 black Fungus creature tokens with "This creature can't block," where X is the number of times you descended this turn.

Landfall — Whenever a land you control enters, create a 0/1 green Plant creature token. If you control seven or more lands with different names, create a 2/2 black Zombie creature token instead.
Land cards in your graveyard have dredge 2.

Haste
Into the TARDIS — Whenever The Ninth Doctor becomes untapped during your untap step, you get an additional upkeep step after this step.

Menace, trample, reach
Squirrels you control have "{T}: Target Squirrel gets +2/+2 and gains trample until end of turn. Activate only as a sorcery."
Whenever one or more Squirrels you control deal combat damage to a player, draw a card.

Flying
Other Birds you control get +1/+1.
{G}, {T}: Create a Birds of Paradise token.
If The Paradise Bird is your commander, your deck can include cards of any color identity.

Haste
{1}, {T}: Copy target activated or triggered ability you control from another legendary source that's not a commander. You may choose new targets for the copy.

As The Pleasant Taxer enters the battlefield, choose casting creature spells, casting noncreature spells, searching libraries, drawing a card beyond the first each turn, or activating abilities other than mana abilities.
Doing the chosen action costs players {1} more.

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever one or more +1/+1 counters are put on a creature you control, exile the top card of your library. Until end of turn, you may play that card.

This spell costs {X} less to cast, where X is the total toughness of creatures you control.
Defender
{2}{U}{U}: 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.

If The Prismatic Piper is your commander, choose a color before the game begins. The Prismatic Piper is the chosen color.
Partner

Whenever The Rani enters or attacks, create a red Aura enchantment token named Mark of the Rani attached to another target creature. That token has enchant creature and "Enchanted creature gets +2/+2 and is goaded."
Whenever a goaded creature deals combat damage to one of your opponents, investigate.

At the beginning of each end step, if a player discarded a card this turn, create a 1/1 black Bird creature token with flying and "This creature can't block."
{3}{B}, {T}: Each opponent discards a card. Activate only as a sorcery.

You may look at the top card of your library any time.
As long as The Reality Chip is attached to a creature, you may play lands and cast spells from the top of your library.
Reconfigure {2}{U}

At the beginning of your upkeep, put a random card from outside the game into your hand. (In Commander sealed, that's everything you didn't play with. In any other commander game, find a way to select a random Magic card.)
{T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs.

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

If The Rhystic Storyteller is your Commander, your deck can't use sleeves.
Whenever you cast a spell with ten or more words of flavor text, draw a card unless an opponent pays {1}.

Whenever The Roaring Toeclaws or another creature you control with mana value five or greater becomes untapped, put +1/+1 counters on it equal to its power.

[+1]: Draw a card, then discard a card.
[+1]: Target creature gets +2/+0 and gains first strike and trample until end of turn.
[–8]: Draw four cards. When you do, The Royal Scions deals damage to any target equal to the number of cards in your hand.

At the beginning of your upkeep, each opponent loses X life and you scry X, where X is the number of Zombies you control.
{2}{U}{B}: Exile target creature card from a graveyard. Create a token that's a copy of it, except it's a 4/4 black Zombie.
When The Scarab God dies, return it to its owner's hand at the beginning of the next end step.

Other Merfolk you control get +1/+1.
When The Scholar of Seas enters the battlefield, choose one of the following cards at random and create a token that's a copy of it:
• Judge of Currents
• Merrow Reejerey
• Lord of Atlantis
• Merfolk Sovereign
• Sygg, River Guide
• Kumena, Tyrant of Orazca

Whenever a creature with a -1/-1 counter on it dies, draw a card.
{1}{B}{R}: Put a -1/-1 counter on another target creature.
When The Scorpion God dies, return it to its owner's hand at the beginning of the next end step.

Players have no maximum hand size.
How Civil of You — At the beginning of your end step, each player may draw a card. Each opponent who does can't attack you or permanents you control during their next turn.

Whenever The Seventh Doctor attacks, choose a card in your hand. Defending player guesses whether that card's mana value is greater than the number of artifacts you control. If they guessed wrong, you may cast it without paying its mana cost. If you don't cast a spell this way, investigate.

Time Lord's Prerogative — Whenever you cast a historic spell, copy it, except the copy isn't legendary. This ability triggers only once each turn.