Reveal the top X cards of your library. Put all land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order.

Spell mastery -- If there are two or more instant and/or sorcery cards in your graveyard, untap those lands.

Creatures you control have base power and toughness X/X until end of turn.

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Counter target spell unless its controller pays {X}.

{T}: Add one mana of any color in your commander's color identity.

Sacrifice Commander's Sphere: Draw a card.

Target creature gets -X/-X until end of turn.

Gain control of target creature with mana value X or less.

Enchant creature

Endless Scream enters the battlefield with X scream counters on it.

Enchanted creature gets +1/+0 for each scream counter on Endless Scream.

Destroy each nonland permanent with mana value X or less.

Equipped creature gets +2/+2 and has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever Grafted Exoskeleton becomes unattached from a permanent, sacrifice that permanent.

Equip {2}

Target creature gets +X/+0 until end of turn.

Maga, Traitor to Mortals enters the battlefield with X +1/+1 counters on it.

When Maga enters the battlefield, target player loses life equal to the number of +1/+1 counters on it.

+2: Scry 2.

0: Look at the top card of your library. If it's a land card or a creature card with mana value less than or equal to the number of loyalty counters on Nissa, Steward of Elements, you may put that card onto the battlefield.

-6: Untap up to two target lands you control. They become 5/5 Elemental creatures with flying and haste until end of turn. They're still lands.

Opulent Palace enters the battlefield tapped.

{T}: Add {B}, {G}, or {U}.

Choose two --

• Target player loses X life.

• Return target creature card with mana value X or less from your graveyard to the battlefield.

• Target creature gets -X/-X until end of turn.

• Up to X target creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Return target nonland permanent with mana value X to its owner's hand.

Draw a card.

Sigil of Distinction enters the battlefield with X charge counters on it.

Equipped creature gets +1/+1 for each charge counter on Sigil of Distinction.

Equip--Remove a charge counter from Sigil of Distinction.

Strive -- This spell costs {1}{G} more to cast for each target beyond the first.

Choose any number of target creatures. Double the number of +1/+1 counters on each of them.

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)

Counter target spell with mana value X.

Squall Line deals X damage to each creature with flying and each player.

Target player gains X life.

Exile X target cards from target player's graveyard. For each card exiled this way, that player loses 1 life and you gain 1 life.

Thornwood Falls enters the battlefield tapped.

When Thornwood Falls enters the battlefield, you gain 1 life.

{T}: Add {G} or {U}.

Any player may cast spells as though they had flash.

Your opponents can't cast spells during your turn.

Target creature gets +X/+X until end of turn.

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.