Menace
Drop — Lurking Glitch enters with two +1/+1 counters on it if you didn't cast any creature spells during your last turn.

Magdalena Bay enters tapped.
{T}: Add {G}, {W}, or {U}.
{VP}{VP}{VP}{VP}, Discard Magdalena Bay: Target creature gets +3/+3 and gains menace until end of turn.

Exile the top X cards of target opponent's library. You may play those cards for as long as they remain exiled, and you may pay {VP}{VP}{B} rather than pay the mana costs of those spells.

Deathtouch
Drop — When Malicious Mech enters, each player sacrifices a creature. If you didn't cast any creature spells during your last turn, instead each opponent sacrifices a creature.

Enchant land you control
Enchanted land is a 2/2 Elemental creature with vigilance, haste, ward {1}, and “{T}: Add two mana of different colors.” It's still a land.
If enchanted land would leave the battlefield, instead sacrifice Manifest the Lightveins and that land gains indestructible until end of turn.

When Masked Duo enters, tap up to one target creature. If you control an artifact, that creature doesn't untap during its controller's next untap step.

Target creature you control gets +2/+2 until end of turn. It fights target creature you don't control.

Equipped creature gets +0/+1 and has vigilance.
Equipped creature assigns combat damage equal to its toughness rather than its power, and can attack as though it didn't have defender.
Equip {2}

Exile the top three cards of your library. You may play up to two of those cards this turn.

Drop — When Morasha Moshlord enters, if you didn't cast any creature spells during your last turn, all creatures get +2/-2 and gain menace until end of turn.

Moresso, Infuser of Light is all colors.
Hexproof from monocolored
Whenever you cast a spell with four or more mana symbols in its mana cost, add four mana of different colors. This ability triggers only once each turn.

Mykian, Pop Paragon enters with a +1/+1 counter on it for each color of mana spent to cast it.
Remove two counters from Mykian: Draw two cards.

Nascent Lightvein enters tapped.
As Nascent Lightvein enters, choose a color. Then if you control three permanents that could each produce a different color of mana, untap it.
{T}: Add one mana of the chosen color.

Creatures you control get +2/+0 until end of turn. Up to one target Elemental you control gains first strike until end of turn.

[+1]: Exile the top card of your library. You may play it this turn. If that card doesn't share a name with a permanent you control or a card in your graveyard, add {R}{R}.
[–2]: Gain control of target creature until end of turn. Untap that creature. It gains haste and menace until end of turn.
[–6]: You get an emblem with “Whenever you amp it up, this emblem deals 2 damage to any target.”

When Neon Colossus dies, draw a card.

Flying, first strike
While you're looking at one or more cards on top of your library except while searching, you may reveal Niokana Headliner from among them and put it into your hand.

Destroy target creature if it has fewer colors than the number of colors of mana spent to cast this spell.

Look at the top X cards of your library, where X is one plus the number of differently named lands you control. Put up to three of them into your hand and the rest on the bottom of your library in a random order.

Create three 1/1 red and green Elemental creature tokens.

This spell costs {2} less to cast if it targets a creature you control with power 4 or greater.
Target creature you control deals damage equal to its power to target creature you don't control.

Lifelink
Whenever you gain life, noncreature spells your opponents cast cost {1} more to cast until your next turn. This ability triggers only once each turn.

Ozzen Headquarters enters tapped.
{T}: Add {W} or {B}.
{T}, Discard another card named Ozzen Headquarters: Draw a card.

Whenever you scry, each opponent loses X life and you gain X life, where X is the number of cards you looked at.
{2}{W}{B}: Scry 1.