Stealth Expert

Someone who is very good at remaining hidden. Security cameras? No problem. Camouflage? Got it covered. Usually they will have some sort of tranquilizers or equipment to jam electronics. In a wartime setting you will often find one of these. These people have stealth down to an art form, normally outclassing anyone in real life.

This ability often enables them to infiltrate areas while dressed in a ridiculously conspicuous costume, rather than using camoflague like a normal sane human being. If done too much, it make break the Willing Suspension of Disbelief. Some stealth experts are also Masters Of Disguise, although they do not use this skill as often as the audience might expect.

Often capable of Stealth Hi Bye and Offscreen Teleportation.

Anime

 * Laffitte from One Piece is capable sneaking into Mariejois with three Warlords of the Sea on the grounds...while wearing tap shoes.
 * While Lupin III often gets into buildings via disguise, he is also an accomplished second story-man. He can sneak in in a black cat suit, or cause enough distractions that his bright yellow tie and bright red jacket aren't noticed.

Comic Books

 * Batman.
 * Dick Grayson and Tim Drake also fit this, being two of his protégés.

Film
"Sergeant Major: Soldier, how did you get so close to me? Chavez: Sniper approached the instructor by being a sneaky bastard, Sergeant Major!"
 * Invisible Boy of Mystery Men is great at being invisible - as long as nobody's looking at him.
 * In The Film of the Book Clear and Present Danger the sniper Chavez was so good, in a controlled test he was able to sneak up on his instructor, using a cheeseburger wrapper as a decoy.


 * Batman in most of his movie adaptations.

Literature

 * The High-Elves in Lord of the Rings were capable of moving silently and unseen in the woods. Hobbits were also capable of great stealth, or so it seemed to a big, clumsy human.
 * The Animorphs naturally excel at this. Flies, fleas and even roaches are among their most common morphs.
 * Corvin Wergard, a private detective from James H. Schmitz's Federation of the Hub series, is an expert at lockpicking and staying hidden.
 * In the X Wing Series, Tyria Sarkin is brought into Wraith Squadron largely for her training in "silent movement in difficult terrain".
 * Force-Sensitives, in much of the Star Wars Expanded Universe, are capable of this using the Force. Tyria herself is Force-Sensitive, though weakly so.
 * In the Star Trek Novel Verse, Garak. His identity in the Obsidian Order was "Agent Regnar" (a Regnar being a small animal capable of changing colour and texture so as to blend into its surroundings). Garak achieves his stealth through a meditative technique that allows him to "blend" his personal energy signatures into the background energy fields. It's hinted that all Cardassians could in theory learn the technique - if they were paying attention and weren't conditioned into ignoring the deeper realities of life around them. This is an important plot point in Star Trek Deep Space Nine: A Stitch In Time.
 * The Shadow
 * The key ability of Gaunt's Ghosts, with the scouts being even better at it.
 * Ajatasutra, Narses personal henchman and Hitman with a Heart in Belisarius Series.

Live Action TV

 * Some of the hiders in the Monty Python's Flying Circus "How Not to be Seen" sketch.
 * Kari Byron manages to fool a heat-detecting motion sensor using a bedsheet in MythBusters.

Music

 * In The Protomen, the band member the Nightwalker is described as this.

Religion

 * Jesus, in the canonical Gospels, would occasionally slip away from the crowds he taught to pray to God alone. Being able to escape the notice of thousands of people (while being quite popular) definitely qualifies him.

Tabletop Games

 * Rogues in Dungeons & Dragons are the designated stealth specialists, though any character can put ranks in the "move silently" and "hide" skills. Furthermore, the Ranger class and some "prestige classes" get the "Hide in plain sight" ability.
 * Exalted tends to have various splats with Stealth as a Favored Ability. Among the Solars, they're the Night Castes. Not only do they have Charms that allow them to go utterly unnoticed, but their Caste ability gives them the power to mute their Anima Banner, meaning they can do some tremendous things without lighting up like a Christmas tree like other Exalts.
 * Vampire: The Masquerade has this as the main gimmick of the Nosferatu clan. Due to their unfortunate appearance and their talents in the Discipline of Obfuscate, they often serve as Konwledge Brokers and whisper mills, able to get in anywhere to dig up dirt.
 * Vampire: The Requiem passes the gimmick on to the Mekhet, who have Auspex in addition to Obfuscate, meaning they can get in anywhere and dig up anything. The Nosfertau still have Obfuscate, but now it's more about being the monster lurking in the darkness.

Video Games

 * Sam Fisher and his colleagues from Splinter Cell.
 * Garrett, from Thief. The Keepers who trained him specialize in stealth as well. Indeed, the first game shows him being recruited because he actually managed to spot (and attempt to pickpocket) his soon-to-be mentor in a crowd.
 * Solid Snake from the Metal Gear series is definitely one of these.
 * Cyrus in Dawn Of War 2. The fact that he and his scouts can be cloaked and sent in and plant extremely powerful traps and explosives almost makes him a Game Breaker with the right upgrades (using him in one mission is also the only way to avoid killing marines who are loyal, but think you've turned traitor, thus assuring you get the Golden Ending).
 * Master thief Kasumi Goto and assassin Thane Krios in Mass Effect 2. Infiltrator!Shepard gets the Tactical Cloak ability.
 * The Spy in Team Fortress 2.
 * The titular Assassins of Assassin's Creed.
 * Batman, in Arkham Asylum and its sequel, Arkham City.
 * The Commandos team.
 * Rogues in Dragon Age get a Stealth score. Maxed out, they can enter stealth any time, which prevents enemies from seeing you until you attack. The expansion pack also gives a prestige class called the Shadow, which lets you stay near invisible all the time.
 * Rangers and Snipers can become invisible in Final Fantasy Tactics A2, so that they can't be targeted by enemies until they perform an action.
 * Rogues in World of Warcraft have the ability to go into "stealth" mode (which translates to very limited aggro radii in PvE and invisibility in PvP). They gain several ambush moves, as well as the ability to pick pocket. They get even more stealth related abilities if they specialize in the subtly talent tree (e.g. the ability to teleport straight behind enemies).
 * City of Heroes has the Stalker archetype as well as the Concealment power pool.
 * JC Denton can be this or an One-Man Army (Or a hybrid), depending on the upgrades the player has chosen.
 * Price and MacMillan during the All Ghillied Up mission in Call of Duty: Modern Warfare.
 * SPARTAN-IIs are said to be this in the Halo universe, and some Elites are as well.
 * You can become one in Knights of the Old Republic.
 * Some classes in Star Wars Battlefront.
 * The Burger King in Sneak King.
 * In Mabinogi, the elf's hide skill could count as this.
 * Kyle "Shadow Simmons from Jagged Alliance 2.

Web Comics

 * There was a strip in Brawl in the Family where Solid Snake, THE master of Tactical Espionage Action, gets out-stealthed by another Brawler... specifically, Mr. Game-And-Watch, who is two-dimensional and completely black, allowing him to literally become one with the shadows.
 * Hella Jeff seems to have a great knack for hiding in vents and behind store shelves to observe Sweet Bro's shenanigans.

Universal

 * Ninjas
 * Well - this, or...
 * Batman

Real Life

 * Animals such as flounder and octopuses can do this (and make a cunning escape as well!)
 * Cats (all sizes) are essentially made for this trope. They have mottled coats to blend in with foliage, padded paws to muffle the sound of their footsteps, antibacterial saliva which kills odours (and explains why they groom so obsessively) and they also possess night vision. It gets even better: they have a distinct gait which minimizes their profile (one side first, then the other), hypersensitive hearing and smell, and whiskers which act as feelers in the dark.
 * Submarines