Mathemagics

Target player draws 2ˣ cards. (2⁰ = 1, 2¹ = 2, 2² = 4, 2³ = 8, 2⁴ = 16, 2⁵ = 32, and so on.)

Improvisation Capstone

Exile cards from the top of your library until you exile cards with total mana value 4 or greater. You may cast any number of spells from among them without paying their mana costs.
Paradigm (Then exile this spell. After you first resolve a spell with this name, you may cast a copy of it from exile without paying its mana cost at the beginning of each of your first main phases.)

Daydream

Exile target creature you control, then return that card to the battlefield under its owner's control with a +1/+1 counter on it.
Flashback {2}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Exhibition Tidecaller

Opus — Whenever you cast an instant or sorcery spell, target player mills three cards. If five or more mana was spent to cast that spell, that player mills ten cards instead.

Practiced Offense

Put a +1/+1 counter on each creature target player controls. Target creature gains your choice of double strike or lifelink until end of turn.
Flashback {1}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

The Dawning Archaic

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Reach
Whenever The Dawning Archaic attacks, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to that card's mana value.

Grave Researcher

At the beginning of your upkeep, surveil 1. Then if there are three or more creature cards in your graveyard, this creature becomes prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Grave Researcher // Reanimate

Pox Plague

Each player loses half their life, then discards half the cards in their hand, then sacrifices half the permanents they control of their choice. Round down each time.

Living History

When this enchantment enters, create a 2/2 red and white Spirit creature token.
Whenever you attack, if a card left your graveyard this turn, target attacking creature gets +2/+0 until end of turn.

Rapturous Moment

Draw three cards, then discard two cards. Add {U}{U}{R}{R}{R}.

All Aboard

Exile target non-Pilot creature you control, then return that card to the battlefield under its owner's control.

Skycoach Conductor

Flash
Flying, vigilance
This creature enters prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Skycoach Conductor // All Aboard

Dina's Guidance

Search your library for a creature card, reveal it, put it into your hand or graveyard, then shuffle.

Ennis, Debate Moderator

When Ennis enters, exile up to one other target creature you control. Return that card to the battlefield under its owner's control at the beginning of the next end step.
At the beginning of your end step, if one or more cards were put into exile this turn, put a +1/+1 counter on Ennis.

Antiquities on the Loose

Create two 2/2 red and white Spirit creature tokens. Then if this spell was cast from anywhere other than your hand, put a +1/+1 counter on each Spirit you control.
Flashback {4}{W}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Fix What's Broken

As an additional cost to cast this spell, pay X life.
Return each artifact and creature card with mana value X from your graveyard to the battlefield.

Flashback

Target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Rabid Attack

Until end of turn, any number of target creatures you control each get +1/+0 and gain "When this creature dies, draw a card."