Swiss Army Hero

Not actually badass soldiers from the Alps (though it's reasonable mistake), this is a combination Video Game Trope and Shapeshifting Trope, this describes a game in which the main character can shape-shift into multiple forms. Each form can be used to do something specific - a water-based one to swim, an earth-based one to be The Big Guy, an air-based one for speed, etc. In some games these would be different characters, forming a party, but in this one it's all the same guy.

Outside of video games, this kind of hero is often headlining a Merchandise-Driven show - after all, more forms means more toys.

Related to Stance System and Tag Team. See also Multiform Balance, Personality Powers and Elemental Powers. Compare Job System, where you only have to change costumes to switch abilities.

Action Adventure

 * The Legend of Zelda Majoras Mask - Link can turn into a Deku, Goron, or Zora, each of which have different abilities.
 * Killer7 is made up of 7 assassins in one body.
 * Aquaria.
 * The titular protagonist of Kameo: Elements of Power.
 * In Castlevania: Order of Ecclesia there are three glyphs that change Shanoa's form into a cat-woman, bat-woman, and little robot thing.
 * Years before, Alucard of Symphony of the Night could change into a fire-breathing bat, a wolf that can run through enemy or mist. The mist could even be upgraded to Deadly Gas.
 * Metal Mutant has the titular character able to transform on-the-fly into a humanoid cyborg, a dinosaur and a bulky tank-bot; each form is extremely specialized - several enemies can be beaten only with a specific one (for example, only the Dino's bite and tail fire can hit low critters).
 * Project Altered Beast for the PS2 gave Luke 9 different forms each with their own powers and abilities, these forms include a Werewolf, Merman, Wendigo, Garuda, Minotaur, Dragon,,  and a
 * This is the main gimmick of Trine. You play as a fighter, an archer, and a mage, all sharing the same body.
 * In Bayonetta, the titular heroine and the antagonist Jeanne, can change into a panther, bat, or crow depending on attribute the situation calls for. According to notebooks found in the game, this was just an ability of all Umbran witches.
 * Chomp of Monster Tale can "evolve" into different forms at will.

MMORPGs

 * The Druid class in World of Warcraft is essentially this. They can access different forms which give them abilities similar to another class (e.g. cat form gives the same combat style as a Rogue, bear gives them better armur so they can tank like a Warrior), act as transport (e.g. fast form, flying form and swimming form) or completely unique (e.g. tree form improves their healing).
 * In Eden Eternal the player can cycle through the game's 15 classes at any time:
 * Warrior, Knight, and Templar (thankfully not the insane kind), tanking.
 * Thief, Martial Artist, and Blade Dancer, melee DPS.
 * Hunter, Engineer, and Ranger, ranged DPS.
 * Cleric, Bard, and Shaman, healing and buffing.
 * Magician, Illusionist, and Warlock, magic DPS.

Platform Game

 * Super Mario Bros. - Namely when one of the bros or anyone else using a Transformation Trinket in stock.
 * Demons Crest - Firebrand has about five or six different forms, which he can shift between at will.
 * Wonder Boy III the Dragons Trap allowed the hero to transform into a dragon, lion, mouse, etc. He had to find a room to do the transformation though.
 * Mega Man ZX. You gain the ability to transform into 6 different forms in the first game, and 15 different forms in the second.
 * Kirby gains various powers depending on what enemy he swallows.
 * Kid Chameleon gave you various masks or helmets to transform you into differently-superpowered characters.

Role Playing Game

 * Shadow Hearts, sort of - Yuri can turn into different demons but there are other party members as well.
 * The sloth demon's Fade level in Dragon Age.
 * Mystic Ark contains a slight variant: while the hero(ine) never changes form, (s)he is joined by two spirits who can each be made to inhabit one of several wooden figurines, bringing them to life as various allies (fighter, mage, cleric, ninja, etc.). You can move those spirits around pretty much anytime outside of battle.
 * Deoxys from the Pokémon games has 4 different forms that can be changed depending on the game in the Advance generation, or using some meteorites in the DS games. The forms are a normal one that acts as Jack of All Stats, a Glass Cannon attack form, a Stone Wall Defense form and a Fragile Speedster form. Another Pokemon that can change forms is Rotom, each of these forms gives him increased stats compared to his base form (the five forms have the same stats), a different Elemental power, and as of Gen V, its Ghost typing is swapped out for one matching that of the appliance it's possessed.
 * The protagonists of Kingdom Hearts: Birth By Sleep can get spells that let them transform into different Unversed in the Final Mix version of the game.
 * Most of the Mega Man Battle Network games starting with BN2 allow MegaMan to change into different variants.
 * BN2 and BN3 had Style Change, where MegaMan's body changes color and a certain part of his body is changed to reflect that Style's element (Heat, Aqua, Elec, or Wood) and specialty. They have one particular attribute (an improved buster, greater defense, more chips per turn, being able to carry more Navi chips and being able to get V4 and V5 Navi chips, turning invisible with each charge shot, being able to change the field, or receiving random good or bag bugs at the start of the battle) combined with one of the four aformentioned elements. You could switch between 2 in BN2 but could only carry 1 in BN3.
 * BN4 and BN5 had Double Soul, a combination of this trope and Mega Manning, as they are obtained through defeating one of MegaMan's allies in battle. MegaMan's charge shot is changed and he gains certain other attributes, usually an elemental affinity. It is toggled in-battle instead of on the overworld by discarding a chip corresponding to that soul (i.e., a Wood chip in BN5 Team Colonel gives you Tomahawk Soul), but they each have at least one con (Knight Soul's charge shot is only melee range, Magnet Soul is weak to Wood attacks, etc.) and last for 3 turns, which can be increased using Navi Customizer programs. BN5 also had Chaos Unisons, activated by discarding a Dark Chip, where it's the same form with a different color scheme and your charge shot turns into the Dark Chip you discarded, without the bugs or HP penalty you'd get using it by itself. If you fire at the wrong time, however, you'll turn back to normal and MegaMan DS will attack you for 13 seconds, and he's invincible during that time, and the time it takes the shot to fully charge increases with each success. They also only lasted for 1 turn, period.
 * BN4 and BN5 also had Dark Soul, activated by using Dark Chips constantly. There are a few minor differences such as MegaMan becoming darker in appearance and his emotion window gaining a malicious expression, and a few major ones such as not being able to go into Full Synchro, the inability to use certain chips, and being able to use Evil Chips and DS Navi Chips. However it isn't nearly as useful as Double Soul.
 * BN5 had two Crosses, Bass Cross and Solar (Django) Cross, though they're barely similar to BN6's Crosses as they override MegaMan's standard form similar to Styles, sans elemental affinity.
 * Bass Cross can be obtained on the Japanese version using a promotional e-Reader card or obtained in the overseas version via cheating. You can also obtain it on any version of Double Team DS on an original DS or DS Lite if you insert a copy of the GBA version that Bass SP has been beaten on. The abilities and colors of this form depend on which version of the game you're playing, Team Colonel's version being silver and Team ProtoMan's version being gold.
 * Solar Cross can be obtained in Double Team DS simply by having a copy of Boktai 2: Solar Boy Django in the GBA slot. As a reference to the Boktai series' usage of solar power there will be a sun on the upper right corner of the screen that powers up the player's attacks if you're jacked in from an area outdoors.
 * BN6 introduces the Cross System. In contrast to BN5, Crosses here are mostly like Souls, except that they're activated through a submenu on the Custom Screen instead of discarding a chip and you go back to normal if hit by a element countering yours.
 * There is also Beast Out, the ability to tap into Gregar or Falzar's power, gaining a rapid-fire buster, instantly locking on to the closest enemy, the ability to charge non-dimming elementless chips to perform powerful slash attacks, and they can be combined with Crosses to become even stronger. Because of the massive power exhibited, using this ability leaves MegaMan exhausted (which is visibly reflected on his emotion window) and he has to go battles without using it for it to recharge, as it lasts for a maximum 3 turns. If you try to do it while the counter is at 0 you'll go into Beast Over, where MegaMan goes apeshit and rapidly loses health but also goes into autopilot similar to BN5's DarkInvis.
 * The Japan-exclusive mobile phone game Rockman.EXE Legend of Network has Trans Arm, which is the same as Double Soul except it only affects your buster as the name implies and the rest of your body is simply recolored.
 * Similarly, the Mega Man Star Force games all have different transformations per each game.
 * The original has Star Break, activated in battle using a special card. Depending on what version you're playing, you'll turn into Ice Pegasus, Fire Leo, or Green Dragon, each of which have a different charge shot and a Star Force Big Bang activated by countering an enemy's attack. You can obtain the Star Breaks of the other two versions by having a BrotherBand with people on those versions.
 * SF2 has Zerker, Saurian, and Ninja transformations which are similar to Star Break except they can be combined.
 * SF3 has Noise Change, which is pretty much the Cross System from BN6 with the one-at-a-time limitation of BN3's Styles. There are 6 per version, though there's also Rogue Noise in both versions, obtained by refraining from making any BrotherBands with other players.
 * Also the immensely powerful titular Black Ace and Red Joker forms.
 * In each of the Breath of Fire games, Ryu can transform into a variety of different dragons, each with differing abilities.

Rhythm Game

 * Pretty much the whole point of the Hero of Patapon 2 and 3 is to be an extra unit of your class of choice. An extra unit with some pretty awesome trinkets, too...

Anime and Manga

 * Getter Robo, with a land-based, sky-based, and water-based form.
 * Betterman has this power.
 * Tony Tony Chopper from One Piece has, like all Zoan-type users, three basic forms; however, by using his Rumble Ball (a medication he developed), he expands that number to seven: his reindeer form (fast), his human form (strong), his hybrid form (brainy: he can do an Enemy Scan; this is also his usual form, unlike most Zoan users) as well as a form optimized for jumping, defense, striking, and using his antlers. There is yet another form he takes on if he OD's on the Rumble Balls, a terrifying, giant monster. Finally, he claims to have developed more during the Time Skip, but they have yet to be seen.
 * One of the Zoids series featured the main character's Giant Robot Liger getting three different sets of armor named Jäger, Schneider, and Panzer, which greatly enhanced speed, maneuverability, and firepower, respectively.
 * Negi Springfield of Mahou Sensei Negima can go between forms of his Magia Erebia Armationem, his Agilitas Fulminis oriented more towards speed and mobility with less offense and defense while being more alike to his use of wind and lightning, the other - his Sim Fabricatus - with greater strength and defense over a loss of speed. Of note is that The author likes to reference games and RPGs throughout the series (this being one of many), so this can be argued to count as a Shout-Out to the game form of this trope.

Comics

 * Aaron Stack aka Machine Man has all sorts of handy devices.

Literature

 * The titular characters in the Animorphs series are this in spades. By the end of the series, each of the main characters has an arsenal of close to fifty animal forms in a wide variety of different shapes and sizes, though each character has a main group of 4-5 forms that they use most frequently, like a favorite battle form (Rachel's grizzly bear, for example) or a favorite bird of prey form for aerial recon. Most books in the series has them acquiring a new animal form which has abilities that will be particularly useful on their next upcoming mission. For example, on a mission when they needed to retrieve a special item from a pitch-black room, they acquired a bat form and used its natural echo-location to safely navigate through the room.
 * Frank Zhang of The Heroes of Olympus also shows shades of this. Becoming an eagle, grizzly bear, and an elephant to take on a giant.

Live-Action TV

 * There are many Kamen Rider examples, where the hero can change into different forms that specialize in different weapons and/or fighting styles. Kamen Rider Black RX started the idea for the franchise with his Robo Rider and Bio Rider forms, but Kamen Rider Kuuga really got it going.
 * Taken to ridiculous extremes in Kamen Rider Decade, where the main character not only has access to his own powers but also the powers and forms of every previous main Kamen Rider of the Heisei era.
 * After Decade, Kamen Rider Double and Kamen Rider OOO let the heroes mix and match several aspects of their powers. Double had two halves with three variations each (plus three unique combos) for a total of 12, while OOO has three parts with five variations (plus a unique combo) for a grand total of 126 (not counting parts used in movies and promo materials, which drive the number up even further).
 * Even Decade is overshadowed by the Kaizoku Sentai Gokaiger, who have access to all 34 previous Super Sentai teams, for a total of nearly 200 powersets (though each individual Gokaiger usually only uses the member of each past team that matches up with their own color, while the Sixth Ranger uses only the 15 other Sixth Rangers).

Web Comics

 * In El Goonish Shive Grace uses human/squirrel form when she wants to just bounce around, while her "omega form" has telekinesis at the strongest, which allows her to fly and claws that can slowdown an opponent's Healing Factor when she attacks with them. The flame-proof fur seems to be common. As a Greater Chimera, she also supplements her "innate" list with any forms into which she was ever turned, so variants range from her boyfriend (who got Body Swap fetish and Transformation Ray gadget) to catgirl to hedgecat. Elliot eventually acquired a spell turning him into Flying Brick - female and in clothes resembling cheerleader's outfit - or several decoy forms which no one in right mind would be inclined to connect with that one, as they involve  thorough personality shifts - which occasionally have other uses, either to complement Elliot's bad acting or simply to feel differently.

Western Animation

 * This trope is Ben 10s entire gimmick. The titular hero wears the Omnitrix capable of temporarily transforming him into a number of alien forms, each with it's own powers and weaknesses.
 * From the same company is Rex of Generator Rex, who can change parts of his body into various weapons and tools as needed,.
 * One episode of Men in Black The Animated Series involves Agent J being given superpowers. It was supposed to make him a Flying Brick but the source of the powers was replaced with a Swiss Army Knife. So Agent J turned into a literal Swiss Army Hero, his arms turning into the various tools on one of those knives.
 * In the Re Tooled second season of the Iron Man cartoon, Iron Man upgraded his armor so that it could shift into a different design for every situation (subterranean armor, underwater armor, stealth armor, "samurai" armor, etc.). A blatant case of how Merchandise-Driven this trope can be, as each form had its own toy.