msem-instigator

If target creature would leave the battlefield this turn, return it to its owner's hand instead.
Fuse (You may cast one or both halves of this card from your hand.)

Whenever a land you control enters, you may sacrifice a creature. If you do, each opponent sacrifices a creature.
{2}{B}{G}, Sacrifice a land: Draw a card.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
Spells you cast that share a type with the card Chillwhisper Witch engorged cost {1} less to cast.

{T}: Add {C}.
{T}, Pay 1 life: Add {U} or {B}.

{T}: Add {C}.
{T}, Pay 1 life: Add {G} or {U}.

Flying
When Heaven's Eyes enters, create a 1/1 white Bird creature token with flying. Then you gain 1 life for each creature in Heaven's Eyes's pack. (Two or more creatures you control with equal power are in a pack.)

When Shadowlurk enters, if a creature died this turn, put a +1/+1 counter on it.

Desiccated Trail enters tapped unless you control another Desert.
{T}: Add {W} or {B}.

Flying
Glorious end — When Blinded Avenger dies, if it was tapped, destroy target creature you don't control.

Enchant creature
When Angel's Favor enters, draw a card.
Enchanted creature gets +0/+2 and has flying.

When Lust for Life enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Augmented — Whenever a creature you control enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, you may sacrifice Lust for Life. If you do, create a token that's a copy of that creature.

Double the number of each kind of counter on target creature you control.

When Boneweary Warrior dies, you may put a -1/-1 counter on target creature.

When Embrace the Veil enters, you may exile target nonland permanent you don't control until Embrace the Veil leaves the battlefield.
Whenever you cast a spell with mana value 5 or greater, you may put a card exiled with Embrace the Veil into its owner's graveyard and return Embrace the Veil to its owner's hand.

When Mana Potion enters, scry 1, then draw a card.
{2}, {T}, Sacrifice Mana Potion: Add two mana of any one color.

Search your library for a creature card, reveal it, put it into your hand, then shuffle. Then if you control a creature with power 4 or greater, you may pay {4}. If you do, you may put a creature card from your hand onto the battlefield.

Tithe (When this creature enters, you may tap three other artifacts and/or creatures you control.)
When Vindictive Abbot enters, you may have target creature get -1/-1 until end of turn. If Vindictive Abbot's tithe was paid, destroy that creature.

Flash
If an opponent would draw one or more cards except during their draw step, instead they draw a card and you create that many 1/1 white Bird creature tokens with flying.

{T}, Sacrifice Merchant's District: Search your library for an Island or Mountain card and put it onto the battlefield tapped, then shuffle.

When Thunderstep Ved enters, it deals 1 damage to any target.

When Mechanical Mastodon enters, you may return another target permanent you control to its owner's hand.

When Load-Bearing Behemoth dies, destroy target artifact or land.

Put three +1/+1 counters on target land. It becomes a 0/0 colorless Elemental creature with haste that's still a land.
Orchestrate—Sacrifice a land. (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Primal {1}{G}{G} (During your turn, you may cast this spell for {1}{G}{G} instead of playing a land.)
When Swampedge Sentinel dies, return another creature card from your graveyard to your hand.

[+1]: Until end of turn, you may cast a creature card from your graveyard. Creature spells cast this way cost {2} less to cast.
[–2]: Each player discards a card. For each player who discarded a creature card this way, create a 2/1 black Horror creature token.
[–6]: For each player, you may put a creature card from that player's graveyard onto the battlefield under your control.