Target creature you control gets +2/+0 and gains first strike until end of turn. If it's attacking, create a 1/1 white Human creature token that's tapped and attacking.

As an additional cost to cast this spell, remove any number of counters from among creatures you control. This spell costs {1} less to cast for each counter removed this way.
Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.

Return target creature to its owner's hand.

When Ballot Registrar enters, make a pledge.
Activated abilities of nonland permanents you control cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Up to X target creatures you control each get +1/+1 until end of turn. Untap those creatures.

Defender, reach

Tap up to two target creatures. Put a stun counter on each artifact tapped this way.

Ward {2}
{U}: Spells you cast this turn can be cast as though they had flash.

Spells you cast and abilities you activate that target equipped creature cost {2} less. This ability can't reduce the mana in that cost to less than one mana.
Equipped creature gets +1/+1 and has lifelink.
Equip {2}

Ruins you control can't be blocked by creatures with power 2 or less.
{1}, {T}: Put a +1/+1 counter on target Ruin.
Spellcharge 5

Creatures you control with power greater than their base power can't be blocked by more than one creature.
{G}{W}: Target creature gets +1/+1 until end of turn. Activate only as a sorcery.

Flash
When Benthalos of Land and Sea enters, you may pay {X}. When you do, create a token that's a copy of target white or blue enchantment you control with mana value X or less.

Return any number of target creature cards with total mana value twice X or less from your graveyard to the battlefield. They're artifacts in addition to their other types.

When Blackout Grifter enters, each opponent loses 1 life and you gain 1 life.
Cybersoul {3}{B}

Equipped creature gets +1/+2 and has “At the beginning of your end step, put a time counter on Blade of Bright Futures.”
{2}, Sacrifice Blade of Bright Futures: You gain X life and draw X cards, where X is one plus the number of time counters on it. Activate only as a sorcery.
Equip {2}

Equipped creature gets +2/+1 and has “At the beginning of your end step, put a time counter on Blade of Clouded Pasts.”
{2}, Sacrifice Blade of Clouded Pasts: Target player loses X life and discards X cards, where X is one plus the number of time counters on it. Activate only as a sorcery.
Equip {2}

Flash
When Blightfang Zyxthax enters, discard a card. If you do, it gains deathtouch until end of turn.

Flash
When Blind Keelah enters and whenever you cast a spell during an opponent's turn, each opponent loses 1 life and you surveil 1. This ability triggers only once each turn.

Enchant creature
Enchanted creature can't attack or block.

Destroy target artifact creature or creature with flying.

Once each turn, when you play a card from anywhere but your hand, you may create a tapped Treasure token.
{2}{R}: Level 2
At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.
{3}{R}: Level 3
Whenever another permanent you control leaves the battlefield, this Class deals 1 damage to any target.

Braise deals 5 damage to target creature or planeswalker. When it dies this turn, its controller creates a Food token.

Brass Laborer enters with two reach counters on it.

Lifelink
Approval — {5}, {T}: Tap target creature. This ability costs {X} less to activate, where X is the number of colors among permanents you control.