A few that I've come up with for various characters:
Deceit:
You'll Never See It Coming - Your backstabbing nature may not be good in a straight fight, and your best offense is attacking someone who isn't expecting it. You may roll Deceit for one close-range attack, provided your target does not expect it's coming, and may add +1 to the attack roll. (I'd considered adding a 'once per exchange' stipulation, but it seems redundant, given that once you try to stab someone in the ass, it's kind of hard for everyone else around not to catch on, and thus they'll expect it.)
Playing Possum - The best defense is letting them think you're dead. After any failed defense, you may sacrifice your next turn to make a maneuver or block with Deceit to convince your attacker that they finished you off. If the failed defense results in a consequence, roll the Deceit maneuver at +2.
Discipline
I've Seen Worse - You're used to seeing gruesome scenes for one reason or another. Add +2 to Discipline rolls to keep your lunch down when faced by unexpected blood and guts.
Guns:
Short Controlled Bursts - You're trained in combat firing, and know how to put more bullets on target. When wielding an automatic weapon, you may add +2 to the resulting stress on a successful attack by firing in bursts.
Shooting Position - You know how to position yourself to steady your aim. Shooting from a prone position adds +3 to your Guns roll, but you take a -2 penalty to your first Athletics defense after firing.
Rapport
Skilled Interviewer - You're used to talking to people and getting them to open up. Add +2 to Rapport rolls when attempting to get information out of someone.
Stealth:
Jungle Camo - You're better at sneaking around in the great outdoors. When you're in a wooded area, add +1 to any stealth checks to remain hidden.
Weapons:
Quick Counter - You're nimble, and very good at drawing your opponent out of position in their attempts to lay a hand on you. After a successful Athletics dodge in melee, you gain +1 to attack with Weapons, provided you're attacking the same opponent that missed you in the first place.
This last one I would put at Weapons (since that's the character who has it's main defensive skill), but it could fit with any defense, really. Athletics would probably be the default.
Taking The Hit - You're either trained as a bodyguard, or are otherwise just that selfless. Whenever an ally fails a defense and takes a hit that would require a Moderate or higher consequence to avoid being taken out, you may sacrifice your next turn to interpose yourself, taking the blow and rolling your own defense instead, taking the damage instead of your ally.