msem-instigator

When Seeker of Horizons enters, reveal the top three cards of your library. You may put a permanent card from among them into your hand. Put the rest on the bottom of your library in any order.
Recite {1}{U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

Target creature you control fights target creature you don't control.
Flashback {5}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

At the beginning of your end step, you may put a progress counter on Sparkline Harness.
[progress 1-3] Whenever an artifact creature you control attacks, it deals 1 damage to target opponent.
[progress 4+] Whenever a creature you control attacks, it deals 1 damage to target opponent.
Whenever a creature you control attacks, it deals 1 damage to target opponent.

{T}: Add one mana of any type that a land you control could produce.
Augmented — At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, untap Thriving Budling and put three +1/+1 counters on it.

Target player discards a card and loses 2 life.
Draw a card.

Whenever one or more creatures attack you, you may put a -1/-1 counter on target creature.

Haste
At the beginning of combat on your turn, you may have target artifact or enchantment you control become a creature with base power and toughness X/X, where X is its mana value, in addition to its other types and gain haste until end of turn. (If it's attached to a permanent, it becomes unattached.)

Look at target player's hand and the top card of that player's library. Look at the top four cards of your library, then put them back in any order.

Equipped creature has all activated abilities of all creature cards in your graveyard.
Equip {3}

At the beginning of each player's draw step, that player draws two additional cards. At the beginning of their next end step, they discard their hand.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Blood Servant enters, if it engorged a creature card, you draw a card and you lose 2 life.

When Lightblessed Claymore enters, attach it to target creature you control.
Equipped creature gets +2/+0 and has lifelink.
Equip {4}

Whenever you scry, you gain life equal to the number of cards looked at while scrying this way.

Flash
Whenever a permanent with an Adventure you control enters, put a +1/+1 counter on Wandering Dingo.

Flying
Whenever Stingsower attacks, you may pay {3}{B}{B}. If you do, target creature gets -1/-1 for each Insect you control until end of turn.

When Whisperwoods Reclaimer enters, if there are three or more land cards in your graveyard, return target land card from your graveyard to the battlefield tapped.

Prowess

When Prized Holsteins enters, create a 2/2 white Dwarf creature token.
When Prized Holsteins leaves the battlefield, you gain 2 life.

Concord — Temple Attendant gets +1/+1 and has indestructible as long as there are four or more card types among permanents you control.

Flash
Flying

Return target creature card from your graveyard to the battlefield, then rediscover a creature card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a creature card. Otherwise, put it back or into your graveyard.)

At the beginning of your upkeep, you gain 1 life.
Whenever one or more creatures attack you, you gain 1 life.

{T}: Add one mana of any color.
{T}, Sacrifice Unicorn of the Vale: Add three mana of any one color.

Improve {W} ({W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever one or more embattled creatures you control attack, create a 1/1 white Cleric creature token with lifelink. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Destroy target creature. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)