Flying
You don't lose unspent red mana as steps and phases end.
Whenever you cast an instant or sorcery spell, add .
When Electro leaves the battlefield, you may pay . When you do, he deals X damage to target player.

Choose one —
• Target creature gets +3/+3 until end of turn.
• Permanents you control gain hexproof until end of turn.
• Return target creature to its owner's hand.

Whenever one or more non-Toy creatures you control attack a player, create a 1/1 white Toy artifact creature token.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Whenever you attack, target creature gains deathtouch until end of turn. Whenever that creature deals combat damage to a player this combat, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

As this land enters, you may reveal a Merfolk card from your hand. If you don't, this land enters tapped.
: Add or .

Haste
Whenever Ardoz or another creature you control enters, that creature gets +2/+0 until end of turn.
: Create a 1/1 red Goblin creature token with haste. Activate only as a sorcery.

Draw cards equal to the greatest power among creatures you control.
You may cast a spell with mana value 5 or less from your hand without paying its mana cost.

Flying, vigilance
Each instant and sorcery spell you cast has casualty 1. (As you cast that spell, you may sacrifice a creature with power 1 or greater. When you do, copy the spell and you may choose new targets for the copy.)

: Add one mana of any color.
, : Up to X target creatures you control each gain haste until end of turn and can't be blocked this turn except by creatures with haste, where X is the number of Bobbleheads you control as you activate this ability.

: Choose target non-Wall creature the active player has controlled continuously since the beginning of the turn. That creature attacks this turn if able. Destroy it at the beginning of the next end step if it didn't attack this turn. Activate only during an opponent's turn, before attackers are declared.

Artifacts you control have ward . (Whenever an artifact you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays .)
When Elder Owyn Lyons enters or dies, return target artifact card from your graveyard to your hand.

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.
−2: Create a 5/5 black Demon creature token with flying. You lose 2 life.
−8: You get an emblem with ", Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."
Ob Nixilis of the Black Oath can be your commander.

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature of their choice.

Return target card from your graveyard to your hand.

: Add .
, , Sacrifice a Desert: Exile all graveyards.

When Yggdrasil enters, exile all creature cards from your graveyard.
: Exile the top three cards of your library.
, : Put a creature card exiled with Yggdrasil onto the battlefield under your control. It gains haste until end of turn. Activate only as a sorcery.

Whenever one or more creature cards are put into your graveyard from anywhere, venture into the dungeon. This ability triggers only once each turn. (To venture into the dungeon, enter the first room or advance to the next room.)
Create Undead — Whenever you complete a dungeon, return target creature card from your graveyard to the battlefield.

Changeling (This card is every creature type.)
Champion a creature (When this enters, sacrifice it unless you exile another creature you control. When this leaves the battlefield, that card returns to the battlefield.)

Flash
When this creature enters, copy target instant or sorcery spell. You may choose new targets for the copy.

+1: Target player draws two cards, then discards two cards.
−2: Gain control of target artifact.
−6: You get an emblem with "Whenever you cast a spell that targets one or more permanents, gain control of those permanents."