msem-instigator

If you would catalyze, catalyze twice instead. (The next spell you cast this turn costs {1} less to cast.)
You may pay an additional {2} as you cast a spell. If you do, reveal the bottom card of your library. You may put it into your graveyard or on top of your library.

When Bearer of Silk Chains enters, gain control of target nonland permanent until Bearer of Silk Chains leaves the battlefield. If that permanent is a Horror, gain control of it instead.

Look at the top two cards of your library. Put one of them into your hand, then submerge the other. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Draw a card, then create a 1/1 blue Elemental creature token. If you drew three or more cards this turn, create three of those tokens instead.

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Counter target spell unless its controller pays {1} or if it has the same name as a permanent or a card in a graveyard.

Enchant creature
Enchanted creature has base power and toughness 1/1 and is a Frog in addition to its other types.
When enchanted creature deals damage to a player, sacrifice Belittle.

When Benign Whisper enters, return another target creature to its owner's hand.

When Benthic Shipcrasher enters, scry 3.

{T}: Until end of turn, target land is every basic land type in addition to its other types and its name becomes Morphic Sea.

When Benthic Tidebreaker enters, reveal the top card of each player's library and exile one of those cards. You may play that card for as long as it remains exiled, and you may spend blue mana as though it were mana of any color to cast it.
Evoke {1}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Tap up to two target creatures. They don't untap during their controller's next untap step.
Reprise {3}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Enchant Equipment
You control enchanted Equipment.

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Target creature you control becomes a copy of another target creature you control until end of turn.
Showcase {2}{U}{U} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Flying
Bird of Many Feathers can block only creatures with flying.
Whenever you scry, put a +1/+1 counter on Bird of Many Feathers.

Create a 1/1 blue Bird creature token with flying, then put the bottom card of your library into your hand.

Exchange control of two target permanents that share a permanent type.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

This spell can't be countered.
Whenever Bitter Leviathan becomes the target of a spell or ability, exile it. Return it to the battlefield under your control tapped and attacking at the beginning of the declare attackers step on your next turn. It can't be blocked that combat.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Blind Soulcaller envisions an instant or sorcery card, you may tap target permanent.

Prowess

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Bloodchill Risen enters, if it engorged an instant card, return target creature to its owner's hand.

Flying
When Blossoming Hatchling enters, create a Treasure token.

Dominance — If you control the creature with the greatest power or tied for the greatest power, you may pay {U} rather than pay this spell's mana cost.
Counter target spell unless its controller pays {3}.

Flying, prowess