msem-instigator

Defender, lifelink

Create three 1/1 white Soldier creature tokens.

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.)

{T}: Add {U}, {B}, or {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Search your library for a Dragon card, reveal it, put it into your hand, then shuffle. It deals damage equal to its power to you.

Choose target instant spell, sorcery spell, activated ability, or triggered ability. Create a Function token with its effects. Then you may pay {1}{U}. If you do, counter that spell or ability. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell. A spell's effects includes added functions.)

{6}: Until the next time this ability resolves, and as long as Helm of the Infinite and target creature you control are on the battlefield, each other creature is a copy of that creature, and effects that would cause permanents to become creatures cause them to become copies of that creature instead.

Target creature gets +2/+2 until end of turn. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.

Prophetic Flames deals 3 damage to target creature. If you control a Goblin, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

As an additional cost to cast this spell, discard a card or pay {2}.

Equipped creature gets +1/+1 and has deathtouch.
{1}: Serpent Staff becomes a 1/1 green Snake creature with deathtouch and loses all other abilities until end of turn.
Equip {3}

Counter target spell. If that spell is countered this way, put it on the bottom of its owner's library instead of putting it into its owner's graveyard. You may put up to three target cards from your graveyard on the bottom of your library in any order.

Flying, haste
Ride {1}{R} ({1}{R}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

Wraith of the Fens gets +2/+2 as long as you've gained life this turn.

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

Reveal the top four cards of your library. You may put a creature or Revelation card from among them into your hand. Put the rest into your graveyard.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Poisonheart Undead enters, you draw a card and you lose 1 life.

Put target nonland permanent into its owner's library second from the top.

Whenever you draw a card, put a quest counter on Seek Perfection.
At the beginning of each end step, if Seek Perfection has four or more quest counters on it, exile target permanent you control, then return it to the battlefield under your control.

If a source would deal damage to a creature this turn, prevent all but 1 of that damage.

Each player chooses up to half the creatures they control, then sacrifices the rest.

Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)
Blocked creatures you control have first strike.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, discard a card. Then draw a card if an opponent is cursed.

Epic Boss Fight deals 5 damage to target creature or planeswalker.
Menagerie — If there are five or more creature types among creatures you control, Epic Boss Fight deals 3 damage to that permanent's controller.

First strike (This creature deals combat damage before creatures without first strike.)