As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

: Choose a color of a permanent you control. Add one mana of that color.

Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.

Creatures you control get +1/+1.

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Affinity for artifacts (This spell costs less to cast for each artifact you control.)
Draw two cards.

When this artifact enters, scry 2.
Whenever another artifact you control with mana value 3 or greater enters, create a 0/0 colorless Construct artifact creature token with "This token gets +1/+1 for each artifact you control."

: Destroy target tapped creature.

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Serra Avatar's power and toughness are each equal to your life total.
When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Trample
If you tap a permanent for mana, it produces three times as much of that mana instead.

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak. ( can be paid with either or 2 life.)

This creature enters with X +1/+1 counters on it.
: Put a +1/+1 counter on this creature.
Remove a +1/+1 counter from this creature: It deals 1 damage to any target.

Skip your draw step.
Whenever you discard a card, exile that card from your graveyard.
Pay 1 life: Exile the top card of your library face down. Put that card into your hand at the beginning of your next end step.

Hurricane deals X damage to each creature with flying and each player.

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

As this artifact enters, choose an opponent.
At the beginning of the chosen player's upkeep, this artifact deals X damage to that player, where X is the number of cards in their hand minus 4.

Flash
You may cast legendary spells and artifact spells as though they had flash.
If a legendary permanent or an artifact entering or leaving the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

When Mu Yanling enters, create a 3/2 colorless Vehicle artifact token with crew 1.
Vehicles you control have flying.
Whenever one or more creatures you control with flying deal combat damage to a player, draw a card.

, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.