Whenever another creature you control enters, it gets +2/+0 and gains haste until end of turn.
When Enduring Courage dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Whenever another creature enters, you gain 1 life.

Artifact creatures and Heroes you control get +1/+1 for each Artificer you control and each Artificer card in your graveyard.
A deck can have any number of cards named Cid, Timeless Artificer.
Cycling (, Discard this card: Draw a card.)

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
, , Sacrifice a creature: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

When this creature enters, it deals damage equal to its power to any target.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Choose target instant or sorcery spell that targets only a single permanent or player. Copy that spell for each other permanent or player the spell could target. Each copy targets a different one of those permanents and players.

When this creature blocks a creature, destroy both creatures.

Enchant player
At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.

Whenever a nontoken creature you control enters, you may pay . If you do, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as this creature is paired with another creature, both creatures have flying.

Ward
At the beginning of your upkeep, exile the top X cards of your library, where X is the number of card types among other nonland permanents you control. You may play those cards this turn.

Whenever a player casts a spell with mana value 3 or less, this creature deals 2 damage to that player.

This creature gets +1/+1 for each enchantment on the battlefield.

, : Two target players exchange life totals.

Flying
, : Add one mana of any color. ( is the untap symbol.)

Flip a coin until you lose a flip or choose to stop flipping. If you lose a flip, Fiery Gambit has no effect. If you win one or more flips, Fiery Gambit deals 3 damage to target creature. If you win two or more flips, Fiery Gambit deals 6 damage to each opponent. If you win three or more flips, draw nine cards and untap all lands you control.

Add for each tapped land your opponents control.

Trample, firebending 4, haste
If you would lose unspent mana, that mana becomes red instead.
Ozai has flying and indestructible as long as you have six or more unspent mana.

Whenever you cast a noncreature spell, create a Clue token. (It's an artifact with ", Sacrifice this token: Draw a card.")
: Until end of turn, target artifact token you control becomes a 3/1 Construct artifact creature with flying.