GURPS/YMMV

Game Breaker: For the most part, GURPS seems content to leave the game breakers in, but charge out the nose for them.
- Unkillable and Supernatural Durability are what they sound like,
  - However, Unkillable could be worked around by, say, jettisoning the character into a nearby star.
- Warp allows a player to go basically anywhere with a thought.
- Super Luck allows you to dictate the out come of ANY 1 roll every so often.
- Word of God: Altered Time Rate costs 100 Character Points. That's 100 points of unfairness against the guy who doesn't have it.
- 3rd edition had the beautiful Eidetic Memory. For 30 points, it halved the cost of all other mental skills.
- Outside of advantages there's Ultra-Tech's inclusion of the Grav Heavy Needler which makes 90% of other man portable weapons obsolete. Forever.
That One Disadvantage: Depending on the GM, this might be any of Easy to Kill, Cursed, Destiny, or Enemy.
- Specifically Cursed means the GM gets to do anything he wants to your character for any reason at any time.
- Destiny is a bit more complex. GM abuse stems from the notion that you don't control how your Destiny (positive or negative) is fulfilled, the GM does. Exact Words can bite you bad if you try to become invincible by taking a seemingly impossible Destiny that involves your death.