A few of these are mentioned with the outfits made for each of the main characters. Elastigirl's is able to stretch as far as she can, Dash's is resistant to the friction created by the super speed, Violet's is designed to disappear when she does.
An aversion of one of the problems with force fields. At the final battle, the Omnidroid is attempting to crush Violet and Dash, who are inside one of Violet's spherical force fields. When it lifts right after Violet is knocked temporarily unconscious, we can see that an indentation in the street has been made in the shape of the force field, suggesting that the force field was acting as an indestructible sphere, transferring the force of the Omnidroid to the street below. In addition, Violet's force fields are typically as invisible as she is, but they flash and ripple according to the amount of energy they're dissipating, implying some manner of energy conversion —from a soft purple hue due to air friction or rolling along the ground, to bright white flashes when hit by bullets or massive impacts.
Mr. Incredible's Super Strength + Nigh-Invulnerability combo is deconstructed. He can't magically anchor himself and when he uses his strength on normal objects, they're visibly warped (grabbing his car to stop from falling, he bends the roof badly enough the door won't close). Rule of Funny, however, when he lifts his car without damaging it further. When he stops a train, he does so by bracing himself and relying on friction; also, he visibly winces just before impact. Finally, when fighting the Omnidroid, it smacks him all over the place because he can't just plant himself at will. Really, the movie is a Deconstruction + Reconstruction of the superhero genre.
Frozone can't just make ice because there needs to be at least some water around. On the other hand, he can make a lot more ice than the air should be able to hold as water vapor. He is also able to use his own body water as a reservoir (to within safe limits; he can't while dehydrated).
In Disney's Tangled, Rapunzel's magic hair must also be magically immune to split ends and other problems that would plague normal hair that hasn't been cut for 18 years. Of course, her hair has very potent healing powers, so keeping hair split end free is relatively minor compared to the other things it's capable of doing.
In Superman vs. the Elite, The Hat is protected by an invisible magical forcefield that not even Superman can break, so he thinks he's invincible. The forcefield lets air through so he can breathe. When Superman creates a massive whirlwind, The Hat ignores it because the wind isn't hurting him... until it sucks away all the oxygen and he passes out.
Elsa, of Disney's Frozen explains in her own song why she can walk around a snowed-over mountaintop and her self-created ice palace in a dress made of frost: "The cold never bothered me anyway". Something is clearly up with her body temperature; while other characters' breathing is visible in the cold, hers is not. She can also walk on ice without slipping, though she can turn this off to effortlessly skate without wearing ice-skates. The books explain that Elsa's skill at math and geometry help her make her ice constructs, otherwise her Ice Palace would have collapsed under its own weight.