msem-instigator

Choose target creature you control and target creature you don't control. Flip a coin. If the coin comes up heads, put one of those creatures on top of its owner's library. Otherwise, put both of them on top of their owners' libraries.

Destroy target non-Xirix permanent. If that permanent had mana value 6 or greater, take an extra turn after this one.

Whenever a creature you control enters, Timid Thunderhorn gets +X/+X until end of turn, where X is that creature's power.

First strike
If one or more creature tokens would be created under your control, for each of those tokens, you may create three 2/2 green Cat Warrior creature tokens instead.

When Tinker Tantrum enters and at the beginning of your upkeep, you may sacrifice an artifact. If you do, reveal cards from the top of your library until you reveal an artifact card with mana value X or less, where X is 1 plus the sacrificed artifact's mana value. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Vigilance
Permanent spells you cast cost {1} less to cast for each 1 damage Tireless Explorer has dealt to players this turn.

Reach
You may have other creatures you control enter as a copy of any creature card in a graveyard with equal or lesser mana value.

Primal {5}{U}{R} (During your turn, you may cast this spell for {5}{U}{R} instead of playing a land.)
Each player discards their hand, then draws seven cards. If this spell was cast for its primal cost, draw cards equal to the number of cards your opponents discarded this way.

You may put cards with mana value 2 or less that permanents you control explore into your hand as though they were lands. (You won't get the counter if you do.)
Whenever Torch of Those Underfoot attacks, it explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then you may put that card in your graveyard.)

Each player sacrifices three lands. Torment each player three times. (To torment a player, they lose 3 life unless they discard a card or sacrifice a nonland permanent.)

Flying
Ward—{2}, Pay 2 life.
At the beginning of your end step, if a card was put into or left your graveyard this turn, put a +1/+1 counter on Tormentor of Graves.

Glorious end — When Toros the Warchief dies, if it was tapped, return it to the battlefield at the beginning of the next end step.
Attacking creatures you control have deathtouch.

Whenever Tortle Veteran or another Turtle you control enters, that creature explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this creature, then put the card back or put it into your graveyard.)

Flash
When Total Surveillance enters, draw a card.
Whenever you cast another spell with flash or an instant, you may pay {1}. If you do, create a 1/1 colorless Drone artifact creature token with flying.

Enchant creature
Enchanted creature gets +3/+3 and has trample.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature dies, target player discards a card.

Rapport — Whenever Trae, Serpent's Grasp and at least one other creature you control become tapped, each player draws a card. Then Trae, Serpent's Grasp deals 2 damage to each opponent with four or more cards in hand.

At the beginning of your end step, choose any number of permanents and/or players, then give each another counter of each kind it already has.
[+1]: Scry 1. Add {U} or {R}.
[–X]: Exile the top X cards of your library. Until end of turn, you may play a card exiled with Trainee Karina Oblay.

Each creature you control enters with an additional +1/+1 counter on it.
When Training Sim enters, create a Function token with “Target creature you control fights target creature you don't control.” (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)

Equipped creature gets +2/+2 and has hexproof and vigilance.
Equip {2}

Land creatures you control get +1/+1 and have vigilance.
Enchantment creatures you control get +1/+1 and have lifelink.
Artifact creatures you control get +1/+1 and have flying.

Choose a nonland card name. Search target player's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles. For each card exiled from their hand this way, you discard a card.

Each player may search their library for a creature card, reveal it, and put it into their hand. Then each player who searched their library this way shuffles it.

Whenever you cast an Aura spell, put two +1/+1 counters on Traveling Thespians.

Once during each of your turns, you may cast an instant, sorcery, or enchantment spell from your graveyard that targets a creature you control.