Modifiers

Enhancements

Strikers
Special Enhancements
Swing Damage: The Strikers' damage is based on Swing instead of Thrust. +50%

Claws
Special Enhancements
Swing Damage: Applied to Talons or Long Talons, allows them to do Swing/Cutting or Thrust/Impaling damage. +50%

Limitations

Psi Modifiers
Special Limitations
Leaves Signature: This is essentially a Nuisance Effect, worth -5% if the signature is only detectable with specialized equipment or through the use of Psi powers, or -10% if it is detectable by a normal person without the aid of special equipment (i.e. leaves a glowing hand print on the victim). If the signature lasts an unusually long period of time (over 24 hours) it's worth an additional -5%

Costs FP
Special Enhancements
Hazard: You may wish to build an ability who's FP cost causes a particular type of Hazard FP, such as Dehydration or Starvation. Treat this is the appropriate Hazard modifier (p. B104), applied directly to the Costs FP limitation. So Starvation FP would be -5% x 1.4 = -7%
Dehydration, -6%
Drowning, -5%
Freezing, -6%
Missed Sleep, -7.5%
Starvation, -7%
Suffocation, -5%

Costs HP
Special Limitations
Radiation: As above, but apply the Radiation modifier (p. B105) directly to the Costs HP limitation:
Radiation Only, -12.5%
Damage & Radiation, -20%

Power Varies with Hit Points/Fatigue Points
Special Limitations
For Advantages this is essentially an Accessibility Limitation: Only while above X HP. Appropriate cost would be:
Only while above 1/2 HP: -30%
Only while above 0 HP: -20%
Only while above -1xHP: -10%
Only while above -2xHP: -5%
Loses 1/4 of it's levels per HP "Threshold", -20%
Loses 1/3 of it's levels per HP "Threshold", -25%
Loses 1/2 of it's levels per HP "Threshold", -30%

For advantages that lose effectiveness if you lose Fatigue points the appropriate with the thresholds for the Accessibility are:
Only while above 3/4 FP, -30%
Only while above 1/2 FP, -20%
Only while above 1/4 FP. -10%
Loses 1/4 of it's levels per FP "Threshold", -15% (at 0 FP the advantage stops functioning).
Loses 1/3 of it's levels per FP "Threshold", -20%
Loses 1/2 of it's levels per FP "Threshold", -25%

For Disadvantages, this is essentially a Mitigator (though mitigators are usually items or substances, I see no reason not to expand it to conditions):
Only while below 1/2 HP: -40%
Only while below 0 HP: -60%
Only while below -1xHP: -80%
Gains 1/4 of it's levels per HP "Threshold", -50%
Gains 1/3 of it's levels per HP "Threshold", -45%
Gains 1/2 of it's levels per HP "Threshold", -40%