Sphere of Resistance

Sacrifice

As an additional cost to cast this spell, sacrifice a creature.
Add an amount of {B} equal to the sacrificed creature's mana value.

Burnt Offering

As an additional cost to cast this spell, sacrifice a creature.
Add X mana in any combination of {B} and/or {R}, where X is the sacrificed creature's mana value.

Molten Gatekeeper

Whenever another creature you control enters, this creature deals 1 damage to each opponent.
Unearth {R} ({R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Lodestone Golem

Nonartifact spells cost {1} more to cast.

Devilish Valet

Trample, haste
Alliance — Whenever another creature you control enters, double this creature's power until end of turn.

Jade Leech

Green spells you cast cost {G} more to cast.

Disruptor Flute

Flash
As this artifact enters, choose a card name.
Spells with the chosen name cost {3} more to cast.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Ruby Leech

First strike
Red spells you cast cost {R} more to cast.

Andradite Leech

Black spells you cast cost {B} more to cast.
{B}: This creature gets +1/+1 until end of turn.

Food Chain

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Lotus Petal

{T}, Sacrifice this artifact: Add one mana of any color.

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Derelor

Black spells you cast cost {B} more to cast.

Ashnod's Altar

Geist-Fueled Scarecrow

Creature spells you cast cost {1} more to cast.

Dark Ritual

Thran Dynamo

Sol Ring

Prossh, Skyraider of Kher

When you cast this spell, create X 0/1 red Kobold creature tokens named Kobolds of Kher Keep, where X is the amount of mana spent to cast it.
Flying
Sacrifice another creature: Prossh gets +1/+0 until end of turn.