Fateful Showdown deals damage to any target equal to the number of cards in your hand. Discard all the cards in your hand, then draw that many cards.

Gain control of target creature or Vehicle until end of turn. Untap it. It gains haste until end of turn.
You may cast a spell with mana value 2 or less from your hand without paying its mana cost.

, , Tap X untapped artifacts you control: Look at the top X cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

When Pia Nalaar enters, create a 1/1 colorless Thopter artifact creature token with flying.
: Target artifact creature gets +1/+0 until end of turn.
, Sacrifice an artifact: Target creature can't block this turn.

Choose target artifact or creature. You get (four energy counters), then you may pay an amount of equal to that permanent's mana value. If you do, gain control of it.

When this creature enters, pay (two energy counters). If you can't, return this creature to its owner's hand and you get .

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
: Add .
, , Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Menace
Whenever this creature enters or attacks, you get (an energy counter).
At the beginning of your upkeep, you may pay . If you do, you draw a card and you lose 1 life.

This enchantment enters with seven hour counters on it.
At the beginning of your draw step, draw an additional card and remove two hour counters from this enchantment.
Your maximum hand size is equal to the number of hour counters on this enchantment.
Whenever you discard a card, you lose 1 life.

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.

Whenever an opponent casts a noncreature spell, that player loses 2 life and you gain 2 life.

When this creature enters, you get (three energy counters).
Pay : Put a +1/+1 counter on this creature. It gains hexproof until end of turn.

This land enters tapped unless you control two or fewer other lands.
: Add or .

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)
At the beginning of your upkeep, if you control the artifact with the greatest mana value or tied for the greatest mana value, draw a card.

Return any number of target nonland, nontoken permanents you control to their owners' hands. Draw a card for each card returned to your hand this way.

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for .)
Flying
: This creature gets +2/+0 until end of turn.

This land enters tapped unless you control two or fewer other lands.
: Add or .

Flying
Whenever this creature or another creature you control enters, you get (an energy counter).
Whenever this creature attacks, you may pay . If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.

First strike, menace
Whenever Kari Zev attacks, create Ragavan, a legendary 2/1 red Monkey creature token. Ragavan enters tapped and attacking. Exile that token at end of combat.

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: This artifact deals 50 damage to any target.

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Each other creature you control of the chosen type enters with an additional +1/+1 counter on it.

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for .)
Search your library for an artifact card with mana value X or less, put it onto the battlefield, then shuffle.

This land enters tapped unless you control two or fewer other lands.
: Add or .

Create three 1/1 colorless Servo artifact creature tokens.
You may cast a spell with mana value 3 or less from your hand without paying its mana cost.

Flying
When this Vehicle enters, you get (two energy counters).
Pay : This Vehicle gains lifelink until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

This creature can't block.
, Exile another creature card from your graveyard: Return this card from your graveyard to the battlefield.