msem-instigator

Lifelink
Outskirts Provider enters with a +1/+1 counter on it if a creature attacked this turn and wasn't blocked.

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.

Hexproof
When Overburdened Trader enters, create three 1/1 colorless Construct artifact creature tokens.

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.

When Overconfident Batter dies, if it's enchanted or you cast a spell that targeted it this turn, you gain 3 life.

{G}, Tap an untapped Nymph you control: Overgrown Beast gets +2/+2 until end of turn.

Overgrown Enclave enters tapped.
{T}: Add {G} or {U}.
{4}{G}{U}: Until end of turn, Overgrown Enclave becomes a Turtle creature with ward {2} in addition to its other types.
Scavenge {5}{G}{U}

{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.

Overgrown Siren must be blocked if able.

Trample
Overgrown Spellroot gets +1/+1 for each creature token you control.
When Overgrown Spellroot enters, create four 1/1 black Worm creature tokens.

When Overgrowth Guardian enters, germinate. (Put a +1/+1 counter on a creature or create a 1/1 green Saproling creature token.)

Whenever Overgrowth Host attacks, germinate. Then creatures you control that are Saprolings or have counters on them gain trample until end of turn.
Saprolings you control get +1/+1.

This spell can't be countered.
Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Haste (This creature can attack and {T} as soon as it comes under your control.)

{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.

Whenever you sacrifice a permanent, Overseer of Armies deals 1 damage to each opponent and each battle they protect.

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.

When Overwhelming Paperwork enters or is put into a graveyard from the battlefield, return up to one target creature to its owner's hand.
{3}{U}{U}: Sacrifice Overwhelming Paperwork. Activate only as a sorcery.

Flying
When Owl of the Seven Stars enters, scry 2.

When P-3 Ambusher enters, you may sacrifice a creature or discard a creature card. If you do, draw a card.

Flash
Flying
When P05 Suppressor enters, create a Function token with “Tap target creature. Put a stun counter on it.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Flash
Flying
Whenever you cast another spell with flash or an instant, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)