msem-instigator

{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.)

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.)

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.

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.

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.

Counter target spell unless its controller pays {X}. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Exile cards from the top of your library until you exile an instant or sorcery card. Put that card into your hand, then Overzealous Tutor deals damage to up to one target creature equal to the number of cards you own in exile.

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