msem-instigator

Players can't pay alternative costs to cast spells. (Casting a spell without paying its mana cost is an alternative cost.)

{T}: Add {C}.
{5}{R}{G}, {T}: Transform Settled Satrapy.

If you would draw a card, you may instead choose creature or land and exile cards from the top of your library until you exile a card of the chosen kind. Put that card into your hand and put all other cards exiled this way on the bottom of your library in a random order.

Add {R} and two mana of any one color.
When you next cast a spell this turn, Manifest Irrationality deals 3 damage to any target.

Spells you cast with mana value 4 or greater cost {1} less to cast.

Exile target spell. Then that card's owner may return it to their hand. If they do, draw a card.

Vanishing 5 (This creature enters with five time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever you remove a time counter from Rallios, create a tapped 2/2 black Zombie creature token.

{T}: Add {G}.
{T}: Add one mana of any color. Activate only if you control another Dryad.

Wanderlust — Return target nonland permanent to its owner's hand. If you control four or more differently named lands, you may aetherize that permanent. (To aetherize, create a token that's a copy of it, then exile that token.)

Two target creatures you control each get +2/+1 until end of turn.

[+1]: Creatures you control gain deathtouch until end of turn.
[–1]: Each player loses 3 life unless they discard a card or sacrifice a creature.
[–6]: You get an emblem with “You may play permanent cards from your opponent's graveyards, and you may spend mana as though it was mana of any color to do so.”

You may have Snowfield Doppelganger enter as a copy of any creature on the battlefield, except it has “While a player is choosing targets as part of casting a spell, that player must choose at least one other creature that shares a name with this creature if able.”

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever Seeker of Ruins deals combat damage to a player, put a +1/+1 counter on it.

Survivors you control have vigilance.

If a player has lost life this turn, this spell has flash and can't be countered.
Destroy target tapped creature.

Enchant creature
Whenever enchanted creature becomes tapped, Violent Repercussions deals 3 damage to that creature's controller.

Whenever a creature an opponent controls becomes tapped, put a +1/+1 counter on Chalkira Duelist.

Rhapsody {4}{R}{R} (Pay {4}{R}{R} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Menace

When Gallipot Apothecary enters, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Flash

Target creature gets -1/-1 until end of turn.
Threshold — You may destroy that creature instead if seven or more cards are in your graveyard.

When Hand of the Evil One enters, mill three cards. Draw a card for each Zombie card milled this way.
Unearth abilities you activate cost up to {1} less to activate.

As an additional cost to cast this spell, you may discard two cards. If you do, this spell costs {3} less to cast and it can't be countered.
Exile the top three cards of your library. You may play those cards until the end of your next turn.

{2}{G}: Exile up to three cards from graveyards. Autocrat X, where X is the number of cards exiled this way. (If you don't control an autocrat, put X +1/+1 counters on this. It becomes an autocrat until it has no +1/+1 counters on it.)
Whenever Hegemony Monarch attacks, you may exile target card from a graveyard. If you do, untap it and it gains trample until end of turn.

Trample, haste
When Blazing Fox enters, you may tap an untapped creature you control. If you do, Blazing Fox gets +X/+0 until end of turn, where X is that creature's power.