Some basic ideas, hope some of them are stolen!
Fissure -
card - Spell
Kill all burrowed creatures.
Inferno -
card - Permanent
All
creatures gain +2/-1,
creatures gain -1/-1.
Blizzard -
card - Spell
Delays all of your opponent's permanents for 2 turns.
Tornado -
card - Spell
Deal 4 damage to
and
creatures.
Ascension-
card - Spell
creatures gain +2/+3, but are delayed for a turn.
Mighty Flash -
card - Spell
and
creatures and weapons are delayed for 1 turn.
Quasar -
- Spell
Deal a random amount of damage to all creatures and players. 0-25 for players, 0-10 for creatures.
Ice Dagger -
- Permanent (Weapon)
Deal 3 damage at the end of your turn. Might freeze opponent's weapon or destroy opponent's shield.
Transcendent Reveal -
- Spell
All creatures lose Immortal.
Gaia's Will -
- Spell
Destroy 6 pillars on target cluster. the owner of destroyed pillars gains 30 life.
Sucker Punch -
- Permanent
Each time the opponent hits with a weapon, there's a 25% chance this permanent deals double the damage back.
Dark Crusader -
- Creature
Unholy: Dark Crusader can't target
permanents.
: Endow
Time Passage -
- Spell
Target creature gains +X/-X, where X is equal to the number of permanents you have.