You may play a playtest card you own from outside the game this turn, and mana of any type can be spent to cast it. (In an game of Unknown event commander sealed, these are all the playtest cards you opened but aren't using in your deck.)

When this creature enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Creature and planeswalker spells you cast have affinity for artifacts. (They cost less to cast for each artifact you control.)
+2: Tezzeret deals X damage to each opponent, where X is the number of artifacts you control. You gain X life.
−3: Return target artifact card from your graveyard to your hand.
−8: Exile the top ten cards of your library. Put all artifact cards from among them onto the battlefield.

Flying
When Tiamat enters, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle.

Trample, haste
Cycling
When you cycle this card, shuffle it into your library from your graveyard. If you've cycled a card named Yidaro, Wandering Monster four or more times this game, put it onto the battlefield from your graveyard instead. (Do this before you draw.)

Your opponents can't cast spells during your turn.
: Transform Jennifer Walters. Activate only as a sorcery.

Other Elf creatures get +1/+1 and have forestwalk. (They can't be blocked as long as defending player controls a Forest.)

Flying
When Kokusho dies, each opponent loses 5 life. You gain life equal to the life lost this way.

(: Add or .)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

This land enters with three mining counters on it.
, Remove a mining counter from this land: Add one mana of any color. If there are no mining counters on this land, sacrifice it.

: Regenerate another target Elf.
: Elf creatures you control get +3/+3 and gain trample until end of turn.

This spell can't be countered.
+2: Each opponent gets an emblem with "At the beginning of your upkeep, this emblem deals 1 damage to you."
−3: Chandra deals 3 damage to each non-Elemental creature.
−X: Chandra deals X damage to target creature or planeswalker. If a permanent dealt damage this way would die this turn, exile it instead.

Whenever you attack, you may sacrifice another creature. When you do, choose two —
• Create two 1/1 red and white Soldier creature tokens with haste that are tapped and attacking.
• You draw a card and you lose 1 life.
• Caesar deals damage equal to the number of creature tokens you control to target opponent.

Whenever Decorated Knight attacks, draw a card from your original deck if it's outside the game.

When this creature enters, you may exile another target permanent you control, then return that card to the battlefield under its owner's control.

You may cast Aura and Equipment spells as though they had flash.
Whenever an Equipment you control enters, you may attach it to target creature you control.

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.