True Sight

Things are not as they seem. What you see is not what's truly there. It may be a building rendered Invisible, or a person who has taken the guise of another. It may be Invisible to Normals, hidden by thermoptic camouflage, holographics, a Perception Filter, a Glamour, or even some kind of implausibly specific hallucinogen.

Whatever the case, to see to the heart of the matter, you need the True Sight. This trait cuts through illusions to show objective, absolute truth, rendering all of that stuff above useless. Of course, it may well come at a price, either on a per use basis something or more permanent, such as the loss of your earthly vision. On the other hand, it may just be hereditary, or a natural ability of your particular race, in which case, lucky you. Or it could be an ability bequeathed by some special object.

If possible, try not to overuse it, because it might be hard on your sanity.

While True Sight always involves true perception, it doesn't always give the user the ability to properly interpret what they see. Thus, they may see the truth and still come to an incorrect conclusion, and there may be reliable ways of fooling them.

Often a function of the Evil Eye. Not to be confused with precognition, the domain of Seers, or clairvoyance, usually the viewing of distant places. Often bundled with Supernatural Sensitivity and/or Aura Vision. Supertrope of See-Thru Specs, glasses or other lenses that have this ability, and See the Invisible, which effects only Invisibility. Contrast Glamour Failure, when the illusion has some flaw that can be perceived by normal sight.

Examples of True Sight include:

Anime and Manga

The Hunter Quent Yaden from Wolf's Rain can see through the wolves' humanoid illusions when drunk.
El Hazard has Nanami, who has the ability to see through illusion. She alerts the group to a Shadow Tribe assassin (who was in human guise) at Arlaman and, later, proves pivotal during Makoto's showdown with Galus atop the Eye of God.
- The problem is that she simply can't see the illusions themselves, so most of the time she assumes everyone sees the same things as her.

Film

The sunglasses in They Live! reveal that certain people are really aliens, as well as the presence of subliminal messages.

Literature

Witches and Wizards on the Discworld have the First Sight, and can see what's really there. This is partly because of magic and partly because they have no Weirdness Censor.
Wizards in The Dresden Files can use their Sight at will, with the caveat that anything they see, however wonderful or horrible, can never be forgotten, ever. It remains in their mind's eye, as fresh as if just seen, for the rest of their lives. When Harry catches a glimpse of an ancient horror, he has to rearrange the way he thinks just to make the seizures stop, and even then it's a good while before he stops shuddering.
In Harry Potter, 'Mad-Eye' Moody's false eye can see through solid objects, clothes and incidentally, invisibility cloaks.
Stephen King's The 10 o'clock People - Having quit smoking, and then taking it up again allows you to see the hideous alien forms of the powerful beings that have taken over the human race. They're called Batmen.
Dean R. Koontz's novel Twilight Eyes. Only people with special purple eyes can see the creatures known as Goblins as they really are.
- It's later revealed that this manifests in different way including True Smell.
In Percy Jackson and The Olympians certain human characters where able to see through the mist. Rachel Elizabeth Dare uses this ability to guide Percy and Co through the Labyrinth.
Luis from Valiant and Ironside in the Modern Faerie Tales trilogy can see through glamour and is impervious to enchantments. It's described as "True Sight".
"The Sight" is a form of magic in the Tortall Universe, which allows the gifted person to detect things such as magic, lies, illness, pregnancy, and godhood. There's also Kel's griffin feather headband, which allows her to see through illusions when worn above her eyes.
Inverted in The Sword of Truth: Jennsen (and any of the 'pristinely ungifted') can see the real thing underneath the illusion because she's unable to see or be affected by magic at all, rather than having some magical ability that allows her to break an illusion like many of the other examples.
"Witch Sight" in the Chrestomanci series.
Way back in Journey to the West, this was one of Sun Wukong's many, many powers.

Live Action TV

On Grimm the titular Grimms have the ability to see wesen (creatures revealed to be the basis of all fairytales) when the wesen lose control over their ability to hide their true forms.

Mythology

According to legend, looking through a stone with a natural hole in it allows one to see the fey.

Tabletop Games

Dungeons & Dragons has spells such as True Seeing and See Invisibility which allow the caster to see through various magical illusions.
Mutants and Masterminds includes True Sight as one of its stock Super Senses powers, allowing the user to see through all illusions, all concealment, and see that which is hidden.

Web Original

Chatoyant College: In Book 1 we find out that Dawn has the gift of true sight. Later, we find out this is because Dawn's Aunt Pru was given a special ointment by a faerie man.

Video Games

A major strategy element in StarCraft is the use of optical camouflage, concealment, and cover to be unseen by the enemy. As such, there are several units and building types that have "Detector" status, meaning they are able to thwart such tricks. The same aspect is used in WarCraft 3.
Egoboo has this as a spell.
The Eye of Truth in La-Mulana allows you to see Invisible Monsters.
The Lens of Truth in The Legend of Zelda Ocarina of Time let you see invisible objects and creatures, see through walls that were normally opaque but weren't really there, and also see the contents of chests without opening them (thus avoiding booby traps, and wasting money, ammo, etc. when you can't carry anymore.) It returns in Majoras Mask, and though simply named 'magnifying glass,' the same idea exists as far back as Links Awakening.
Several characters (mostly those with great spiritual power) are able to see Amaterasu's true form in Okami.
The Reveal Psynergy in Golden Sun, which allows one to see through illusions and invisibility.