Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Skewer the Critics

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Skewer the Critics deals 3 damage to any target.

Bedlam Reveler

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Prowess
When Bedlam Reveler enters the battlefield, discard your hand, then draw three cards.

Plains

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Infuriate

Target creature gets +3/+2 until end of turn.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Lightning Helix

Lightning Helix deals 3 damage to any target and you gain 3 life.

Mountain

Clifftop Retreat

Clifftop Retreat enters the battlefield tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Guided Strike

Target creature gets +1/+0 and gains first strike until end of turn.
Draw a card.

Sacred Foundry

({T}: Add {R} or {W}.)
As Sacred Foundry enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Kiln Fiend

Whenever you cast an instant or sorcery spell, Kiln Fiend gets +3/+0 until end of turn.

Leonin Lightscribe

Magecraft — Whenever you cast or copy an instant or sorcery spell, creatures you control get +1/+1 until end of turn.

Rip Apart

Choose one —
• Rip Apart deals 3 damage to target creature or planeswalker.
• Destroy target artifact or enchantment.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Clever Lumimancer

Magecraft — Whenever you cast or copy an instant or sorcery spell, Clever Lumimancer gets +2/+2 until end of turn.