Have

Swamp

Cornered by Black Mages

Target opponent sacrifices a creature of their choice.
Create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."

Maximum Overdrive

Put a +1/+1 counter on target creature. It gains deathtouch and indestructible until end of turn.

Black Mage's Rod

Job select (When this Equipment enters, create a 1/1 colorless Hero creature token, then attach this to it.)
Equipped creature gets +1/+0, has "Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent," and is a Wizard in addition to its other types.
Equip {3}

Flush Out

Discard a card. If you do, draw two cards. (Then shuffle this card into its owner's library.)

Stormshriek Feral

Flying, haste
{1}{R}: This creature gets +1/+0 until end of turn.

Stormshriek Feral // Flush Out

The Darkness Crystal

Black spells you cast cost {1} less to cast.
If a nontoken creature an opponent controls would die, instead exile it and you gain 2 life.
{4}{B}{B}, {T}: Put target creature card exiled with The Darkness Crystal onto the battlefield tapped under your control with two additional +1/+1 counters on it.

Hidetsugu's Second Rite

If target player has exactly 10 life, Hidetsugu's Second Rite deals 10 damage to that player.

The Fire Crystal

Red spells you cast cost {1} less to cast.
Creatures you control have haste.
{4}{R}{R}, {T}: Create a token that's a copy of target creature you control. Sacrifice it at the beginning of the next end step.

Queen Brahne

Prowess
Whenever Queen Brahne attacks, create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."

Burst Lightning

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Burst Lightning deals 2 damage to any target. If this spell was kicked, it deals 4 damage instead.

Blood Crypt

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

Trance Kuja, Fate Defied

Flame Star — If a Wizard you control would deal damage to a permanent or player, it deals double that damage instead.

Kuja, Genome Sorcerer

At the beginning of your end step, create a tapped 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent." Then if you control four or more Wizards, transform Kuja.

Kuja, Genome Sorcerer // Trance Kuja, Fate Defied

Reactor Raid

You may sacrifice an artifact or creature. If you do, draw two cards. (Then exile this card. You may play the land later from exile.)

Midgar, City of Mako

Midgar, City of Mako // Reactor Raid

Black Waltz No. 3

Flying, deathtouch
Whenever you cast a noncreature spell, Black Waltz No. 3 deals 2 damage to each opponent.

Blazemire Verge

{T}: Add {B}.
{T}: Add {R}. Activate only if you control a Swamp or a Mountain.

Circle of Power

You draw two cards and you lose 2 life. Create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."
Wizards you control get +1/+0 and gain lifelink until end of turn.

Vector, Imperial Capital

This land enters tapped.
{T}: Add {B} or {R}.

Mountain

Grab the Prize

As an additional cost to cast this spell, discard a card.
Draw two cards. If the discarded card wasn't a land card, Grab the Prize deals 2 damage to each opponent.

Shock

Lithobraking

Create a Lander token. Then you may sacrifice an artifact. When you do, Lithobraking deals 2 damage to each creature. (A Lander token is an artifact with "{2}, {T}, Sacrifice this token: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.")

Mage Siege

Create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."