msem-instigator

Creature spells you cast cost {1} less to cast.

Whenever you cast a creature or planeswalker spell, if mana produced by a nonland permanent was spent to cast it, it gains trample and haste until end of turn.
{T}: Add {R} or {G}.

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast enchantment spells.

When Keeper of Pearls enters or a creature you control scavenges it, you gain 2 life.
Scavenge {G} ({G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Long-Lived Prowler gets +3/+0 as long as there are four or more card types among cards in your graveyard.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)

{T}: Add {G}.
Once during each of your turns, you may cast a creature spell from your graveyard if there are thirteen or more cards in your graveyard. (You still pay its costs. Timing rules still apply.)

{4}{G}: Monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous.)
When Mountain Bighorn becomes monstrous, you may have it fight target creature you don't control.

When Naive Apprentice enters, each player creates a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
As long as an opponent controls an artifact, Naive Apprentice gets +2/+0.

Nightshade Cultivator has deathtouch as long as five or more cards are in your graveyard.

When Olten Surveyor enters, choose any number. Each opponent creates a 1/1 colorless Servo artifact creature token for each mode chosen.
• Destroy target artifact or enchantment with mana value 3 or less.
• Shuffle up to four cards from target player's graveyard into their library.
• You gain 4 life.

When Paw Valley Pathfinder enters, reveal the top card of your library. If it's a land card, draw a card.

{T}: Add {G}. When that mana is used to cast a spell with mana value 5 or greater, you may untap Performer of Growth and transform it.

Deathtouch
Whenever a +1/+1 counter is put on a creature you control, that creature gains deathtouch until end of turn.

When Refuse Trawler enters, you may pay {G}. If you do, choose one —
• Return a permanent card from your graveyard to your hand.
• Rediscover a permanent card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a permanent card. Otherwise, put it back or into your graveyard.)

Whenever you play a land, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
{1}{G}{U}{R}, Sacrifice three Clues: Exile cards from the top of your library until you exile three nonland cards. You may cast any number of those cards without paying their mana costs.

Once each turn, when another creature you control enters, you may search your library for a card with the same name as that creature, reveal it, put it into your hand, then shuffle.

{T}: For each color among enchantments you control, add one mana of that color.
{2}{G}{G}, Sacrifice Sower of Seeds: Shuffle any number of enchantment cards from your graveyard into your library. Create an X/X black Horror creature token, where X is the number of enchantment cards shuffled into your library this way.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{2}{G}: Put two +1/+1 counters on target land you control. If you're in a renaissance, you may have that land become a 0/0 green Elemental creature until end of turn. (It's still a land.)

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Thuggish Detective can't be blocked by more than one creature.
When Thuggish Detective becomes renowned, you may destroy target noncreature permanent.

Whenever a basic land you control enters, add one mana of any color.

Reach, deathtouch

When Verdant Curtain Mascot enters, choose one —
• You gain 2 life.
• Proliferate. (Choose any number of permanents and/or players with counters on them, then give each another counter of each kind already there.)

{2}, {T}: Tap target creature. This ability costs {2} less to activate if you control an enchantment.

Flying
When Hallowed Perspective enters, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
You may exert Hallowed Perspective as it attacks. When you do, until your next turn, you may cast spells as though they had flash. (An exerted creature won't untap during your next untap step.)