Inti, Seneschal of the Sun

Whenever you attack, you may discard a card. When you do, put a +1/+1 counter on target attacking creature. It gains trample until end of turn.
Whenever you discard one or more cards, exile the top card of your library. You may play that card until your next end step.

Thought Scour

Target player mills two cards.
Draw a card.

Island

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Serum Visions

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Arclight Phoenix

Flying, haste
At the beginning of combat on your turn, if you've cast three or more instant and sorcery spells this turn, return Arclight Phoenix from your graveyard to the battlefield.

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Dragon's Rage Channeler

Whenever you cast a noncreature spell, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — As long as there are four or more card types among cards in your graveyard, Dragon's Rage Channeler gets +2/+2, has flying, and attacks each combat if able.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, Ledger Shredder connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Demilich

This spell costs {U} less to cast for each instant and sorcery spell you've cast this turn.
Whenever Demilich attacks, exile up to one target instant or sorcery card from your graveyard. Copy it. You may cast the copy.
You may cast Demilich from your graveyard by exiling four instant and/or sorcery cards from your graveyard in addition to paying its other costs.

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Spirebluff Canal

Spirebluff Canal enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Faithless Salvaging

Discard a card, then draw a card.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)