Rhystic Cave

{T}: Choose a color. Add one mana of that color unless any player pays {1}. Activate only as an instant.

Rapid Fire

Cast this spell only before blockers are declared.
Target creature gains first strike until end of turn. If it doesn't have rampage, that creature gains rampage 2 until end of turn. (Whenever the creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)

Cyclopean Snare

{3}, {T}: Tap target creature, then return Cyclopean Snare to its owner's hand.

Flailing Manticore

Flying, first strike
{1}: Flailing Manticore gets +1/+1 until end of turn. Any player may activate this ability.
{1}: Flailing Manticore gets -1/-1 until end of turn. Any player may activate this ability.

Camel

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)
As long as Camel is attacking, prevent all damage Deserts would deal to Camel and to creatures banded with Camel.

Cocoon

Enchant creature you control
When Cocoon enters, tap enchanted creature and put three pupa counters on Cocoon.
Enchanted creature doesn't untap during your untap step if Cocoon has a pupa counter on it.
At the beginning of your upkeep, remove a pupa counter from Cocoon. If you can't, sacrifice it, put a +1/+1 counter on enchanted creature, and that creature gains flying.

Quagmire

Creatures with swampwalk can be blocked as though they didn't have swampwalk.

Niall Silvain

{G}{G}{G}{G}, {T}: Regenerate target creature.

Fasting

At the beginning of your upkeep, put a hunger counter on Fasting. Then destroy Fasting if it has five or more hunger counters on it.
If you would begin your draw step, you may skip that step instead. If you do, you gain 2 life.
When you draw a card, destroy Fasting.

Tahngarth's Glare

Look at the top three cards of target opponent's library, then put them back in any order. That player looks at the top three cards of your library, then puts them back in any order.

Camouflage

Cast this spell only during your declare attackers step.
This turn, instead of declaring blockers, each defending player chooses any number of creatures they control and divides them into a number of piles equal to the number of attacking creatures for whom that player is the defending player. Creatures those players control that can block additional creatures may likewise be put into additional piles. Assign each pile to a different one of those attacking creatures at random. Each creature in a pile that can block the creature that pile is assigned to does so. (Piles can be empty.)

Alabaster Leech

White spells you cast cost {W} more to cast.

Spatial Binding

Pay 1 life: Until your next upkeep, target permanent can't phase out.

Goblin Snowman

Whenever Goblin Snowman blocks, prevent all combat damage that would be dealt to and dealt by it this turn.
{T}: Goblin Snowman deals 1 damage to target creature it's blocking.

Glasses of Urza

Sorrow's Path

{T}: Choose two target blocking creatures controlled by the same opponent. If each of those creatures could block all creatures that the other is blocking, remove both of them from combat. Each one then blocks all creatures the other was blocking.
Whenever Sorrow's Path becomes tapped, it deals 2 damage to you and each creature you control.

Goblin Firebug

When Goblin Firebug leaves the battlefield, sacrifice a land.

Shelkin Brownie

{T}: Target creature loses all "bands with other" abilities until end of turn.

Wood Elemental

As Wood Elemental enters, sacrifice any number of untapped Forests.
Wood Elemental's power and toughness are each equal to the number of Forests sacrificed as it entered.