Enchant creature with another Aura attached to it
Enchanted creature gets +3/+3 and has trample, vigilance, and reach.

This spell can't be countered.
Whenever Eviviva enters or attacks, create a 2/2 red Warrior creature token with “Whenever this creature deals combat damage to a player, exile the top card of your library. You may play that card this turn.”

Deathtouch
Other Gorgons, Snakes, and Basilisks you control get +1/+1.
Whenever a creature with deathtouch you control deals combat damage to a player or planeswalker, create a Treasure token.

When Exemplar of Grit dies while attacking, return it to the battlefield tapped under its owner's control with a defender counter on it.
When Exemplar of Grit dies while blocking, return it to the battlefield tapped under its owner's control with a decayed counter on it.

When this creature enters, target player separates their hand into a face-up pile and a face-down pile. Choose one of those piles, reveal it, and choose a nonland card from it. Exile that card until this creature leaves the battlefield.

Flying, vigilance
If you would draw a card, you may exile a card from your graveyard instead. When you do, reveal cards from the top of your library until you reveal a card that shares a card type with the exiled card. Put that card into your hand, and the rest on the bottom in a random order.

Revered
Landfall — Whenever a land you control enters, put a +1/+1 counter on this creature. Then if you control eight or more lands, double the number of +1/+1 counters on this creature.

When this creature enters, create a colorless artifact token named Puzzlebox with “{T}, Discard a card: Draw a card.”
Whenever a creature you control attacks, you may exile a number of cards from your graveyard equal to its power. If you do, put a +1/+1 counter on it.

Exile the top two cards of your library. You may play those cards until you next cast a spell from your hand.
Flashback {3}{R}{R}

As an additional cost to cast this spell, remove a level counter from a creature you control or pay {3}.
Exile target creature or planeswalker. Surveil 2.

Destroy all creatures.

Level up {R/W}
[level 1-2] Whenever a nontoken creature you control with a counter on it dies, create a 1/1 white Citizen creature token.
[level 3+] Whenever a nontoken creature you control with a counter on it dies, create a 4/4 red Error creature token with menace.

Creatures can't attack you or a planeswalker you control unless their controller pays {1} for each of those creatures beyond the first.

Mill X cards. For each land card milled this way, add {B}{B}. For each creature card milled this way, create a 2/2 black Zombie artifact creature token. For each noncreature, nonland card milled this way, draw a card.

Destroy target creature if its mana value is less than or equal to the amount of mana spent to cast this spell.
Flashback {X}{B}{B}{B}

Firebolt deals 2 damage to any target.
Flashback {4}{R}

Haste
Whenever a player casts a spell, if no mana from a basic source was spent to cast it, Flaw in the System deals 2 damage to that player.

Choose target card in another player's graveyard other than a basic land. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. If their library is searched this way, they shuffle it. You gain 1 life for each card exiled this way. That player draws a card for each card exiled from their hand this way.
Flashback {3}{B}

Whenever Forgotten Cultivator attacks, mill three cards. Return a permanent card from among the milled cards to your hand.
Spellcharge 4

This land enters tapped unless you control one or fewer other lands.
{T}: Add {B} or {G}.
Cycling {2}

{T}: Add {C}. You may sacrifice Fortune Bearer. If you don't, you can't spend this mana to cast a spell from your hand.
Surface {5}{U}{U}. Fortune Bearer surfaces transformed.

Flying
If a source would deal 2 or more damage to Fragile Soul, prevent that damage.

Create a tapped Leyshard token.

Whenever you attack, create a 1/1 colorless Soldier creature token that's tapped and attacking.

Exile target creature you control, then return that card to the battlefield under its owner's control.