msem-instigator

Counter target spell if you have more cards in hand than its controller.

Draw three cards, then reveal your hand.

When Over the Horizon enters, scry 1.
{T}: Add {C}.
{1}, {T}: Return Over the Horizon to its owner's hand.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Over the Moon deals 4 damage to up to one target creature or planeswalker.
II, III — Until end of turn, spells you cast with mana value 4 or greater cost {1} less to cast and can't be countered.
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Enchant player
Whenever enchanted player becomes the target of a spell or ability they don't control, if it isn't a copy, its controller copies it.

Counter target spell. For each other card named Overcharge in your graveyard, create a colorless Canister artifact token with “{T}, Sacrifice this artifact: Add {C}.”

Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy. Overclock deals X damage to you, where X is the number of spells you've cast this turn.

Kicker—Sacrifice an artifact or creature. (You may sacrifice an artifact or creature in addition to any other costs as you cast this spell.)
Choose target creature you control. Put a +1/+1 counter on it if this spell was kicked. Then it deals damage equal to its power to target creature you don't control.

Destroy target creature with power 4 or greater. (You need a target to cast this spell.)
Tap up to two target creatures.

Until end of turn, creatures you control have base power X/Y, where X is the greatest base power among creatures you control and Y is the greatest base toughness among creatures you control.
If you control a creature with flying, creatures you control gain flying until end of turn. The same is true for first strike, haste, lifelink, menace, prowess, trample, and vigilance.

Any number of target players each draw seven cards, then discard seven cards.

Target creature gets +2/+1 and gains haste until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Target player reveals their hand. You choose a nonland card from it. That player discards that card unless they discard three other cards.

{T}, Pay 1 life: Add {G} or {W}.
{1}, {T}, Sacrifice Overgrown Refuge: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Overgrown Ruins enters tapped.
As Overgrown Ruins enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Each player discards two cards. Then if there are four or more card types among cards in your graveyard, create two 1/1 white Human creature tokens.

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Overheat deals X damage to any target.

Overkill deals 4 damage to any target that was dealt damage this turn.

{T}: Add {C}.
{7}, {T}: Copy target instant or sorcery spell with {X} in its mana cost. You may choose new targets for the copy. This ability costs {1} less to activate for each instant and sorcery card in your graveyard.

Creatures you control get +3/+3 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

At the beginning of each upkeep, create X 1/1 white Soldier creature tokens, where X is two plus the number of creatures you control.

Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)
Target creature you control fights target creature you don't control.

Creatures you control get +3/+3 until end of turn and creatures your opponents control block this turn if able.

Overwhelming Fusillade deals 4 damage divided as you choose among any number of targets.
If you control a creature with power 4 or greater, Overwhelming Fusillade deals 2 damage to each opponent.

Target opponent reveals their hand. You may choose a noncreature, nonland card from it. If you do, that player discards that card. Otherwise, they lose 3 life.