Myntasha, Honored One

As an additional cost to cast this spell, you may open a sealed Magic booster pack and put the cards on the bottom of your booster pile in a random order.
Spells you cast have booster cascade. (It's like cascade, but use your booster pile rather than your library.)

Euroakus

When Euroakus enters, create a number of 1/1 blue Human Wizard creature tokens equal to the number of differently named lands you control.
{4}{G}{U}: Draw a card for each Wizard you control. They each get +1/+1 until end of turn for each card in your hand.

Kharis & The Beholder

Flying
When Kharis & The Beholder enters and at the beginning of your upkeep, create a 1/1 white Human creature token and make a charisma check. (Roll a d20.)
• If the result plus the number of creatures you control is greater than 11, put a +1/+1 counter on each creature you control.
• If the result is a natural 20, for each nonlegendary creature you control, create a token that's a copy of that creature.

The Secret Lair

{T}: Add {C}.
{T}, Say the secret word: Add one mana of any color. Scry 1. You gain 1 life.

Elusen, the Giving

Flying, vigilance, lifelink, haste
At the beginning of your second main phase, the player to your left gains control of Elusen, the Giving.
Whenever a player donates a permanent to another player, the donating player draws a card, gains 1 life, and creates three Treasure tokens.

Nira, Hellkite Duelist

Flash
Flying, trample, haste
When Nira, Hellkite Duelist enters, the next time you would lose the game this turn, instead draw three cards and your life total becomes 5.