Exile target nonland permanent.

When Audacious Roughrider enters or leaves the battlefield, exile the top card of your library. Then you may discard a card. If you do, put the exiled card into your hand. If you don't, create a Treasure token.
Wander {4}{R}{R}

Favored
Whenever a legendary creature you control attacks, create a tapped and attacking token that's a copy of that creature, except it's not legendary and is an enchantment in addition to its other types.

Flying
Drop — Whenever Avatar of the Airwaves or another creature enters the battlefield under your control, if the entering creature was cast and you didn't cast any creature spells during your last turn, create a token that's a copy of target non-Avatar creature you control.

Menace
Drop — Whenever Avatar of the Decks or another creature enters the battlefield under your control, if the entering creature was cast, sacrifice a permanent unless you didn't cast any creature spells during your last turn.

Vigilance
Drop — Whenever Avatar of the Festival or another creature enters the battlefield under your control, if the entering creature was cast and you didn't cast any creature spells during your last turn, you may have your life total become the total power and toughness of creatures you control.

Haste
Drop — Whenever Avatar of the Moshpit or another creature enters the battlefield under your control, if the entering creature was cast and you didn't cast any creature spells during your last turn, discard your hand, then draw three cards.

Reach
Drop — Whenever Avatar of the Rave or another creature enters the battlefield under your control, if the entering creature was cast and you didn't cast any creature spells during your last turn, return up to two target cards from your graveyard to your hand.

You don't lose unspent mana as steps and phases end.
At the beginning of your end step, if you've spent at least five mana to cast spells this turn, draw a card. If you've spent at least ten, create a 10/10 green Elemental creature token. If you spent at least twenty, you gain 20 life. If you spent at least fifty, you win the game.

Flying
Favored
Whenever your Champion attacks, you may double its power until end of turn. If you do, sacrifice it at the beginning of the next end step.

When Banish to the Isle enters the battlefield, exile up to one target nonland permanent you don't control until Banish to the Isle leaves the battlefield. You gain 3 life.

Up to X target creatures you control each get +1/+1 until end of turn. Untap those creatures.

When Barbarous Roughrider enters or leaves the battlefield, each opponent loses 2 life unless they sacrifice a nontoken creature.
Wander {4}{B}{B}

Barreling Bull can't be blocked by creatures with power 2 or less.
When Barreling Bull enters the battlefield, return a creature you control to its owner's hand.

Lifelink, ward {1}
Whenever Basilo, Lion of Valor attacks, you may bless target nonenchanted creature.

Menace
Bastion Breaker can't block.

Flying
Whenever you amp it up, create a 1/1 colorless Servo artifact creature token.

{4}{B}{B}, Exile Begin the Imperial Era from your hand: At the beginning of your next upkeep, you may cast Begin the Imperial Era from exile without paying its mana cost. Activate only as a sorcery.
You draw three cards and each opponent discards three cards. Each player loses 3 life.

Flash
Ward {3}
You may reveal the second card you draw each turn as you draw it. When you do, you may cast it without paying its mana cost. If you didn't cast a spell this way, create two Treasure tokens.

At the beginning of combat of your turn, Belief-Belying Beast gains flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Trample
When Belligerent Peluda enters the battlefield, it deals 2 damage to any target.

When Blasphemous Bonecaller enters the battlefield or dies, you draw a card and you lose 1 life.
{1}{B}, Discard Blasphemous Bonecaller: You draw a card and you lose 1 life.

Enchant player
Enchanted player may cast blue spells with mana value less than or equal to their devotion to blue without paying their mana costs.

Enchant creature
Enchanted creature gets +2/+2 and has flying.
Whenever enchanted creature dies, create a 2/2 white Pegasus creature token with flying.

Ward {X}, where X is the number of differently named lands you control.