Damping Sphere

If a land is tapped for two or more mana, it produces {C} instead of any other type and amount.
Each spell a player casts costs {1} more to cast for each other spell that player has cast this turn.

Ashnod's Altar

Sphere of Resistance

Lotus Petal

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

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Jade Leech

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

Feroz's Ban

Lodestone Golem

Nonartifact spells cost {1} 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.

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.

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.

Andradite Leech

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

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.