In Alnam no Kiba there are 12 tribes of people that can transform into humanoid animals from the Eastern Zodiac. The 12 main characters are members of these tribes.
Bounce: Bounce, in some versions, can take on the form of other spheres he's met.
Arianna is capable of changing her avatar at will, and initially sports a different form each time you see her. She eventually settles on a permanent look, but still uses shapeshifting to trick the heroes at one point.
One sidequest involves a tribe of amorphous “Phishers,” who kidnap and try to impersonate your party members. Eventually you have to face the Phisher King, who cycles freely between all of them during the battle.
The 1997 Licensed Game for Casper on the Sega Saturn, 3DO and Playstation revolves heavily around Casper slowly unlocking various transformations in order to progress through Whipstaff Mansion:
A Super Smoke form that lets him travel through grated air vents.
A bouncy ball form that lets him bounce up through ceiling vents.
A buzzsaw form to cut through boards sealing up doorways.
A hammer form, used to defeat Fatso's toy tanks in a fight in the attic to retrieve one of the missing Lazarus Machine components.
A lightbulb form, which is used to access a single room in the southern part of the attic.
A fan form and a cyclone form, either of which can used to defeat Stretch in the garden to get a Lazarus piece — the fan by blowing him into his homemade grave, the cyclone by sucking him into it.
A screwdriver form, used to fix the Lazarus Machine.
A "Megacasper" form, used to scare all three of the Ghostly Trio so Casper can retrieve the final Lazarus Machine component, and which can subsequently be used to find hidden rooms.
A spring form, which is used to find a hidden room.
In Castlevania, Dracula and Alucard embody this trope more than any other character in the series. Alucard, being a playable example, can morph into the classic mist, bat and wolf forms at will.
Kheldians in City of Heroes are symbiotic alien energy beings that grant their hosts various powers, including the ability to assume the forms of their previous hosts. In practice, this allows their human hosts to assume two different forms: "nova" and "dwarf".
In DC Universe Online, characters of the Nature power set have several Limit Breaks where they take the form of a wolfman, a gorilla, or a humanoid insect. Sorcery characters, meanwhile, can enhance their abilities by temporarily turning into a giant bat.
The game Death Gate features Sang-Drax, a dragon who uses shapeshifting as defence. Whenever you try to attack, he simply changes to a form that is invulnerable to it. You can either catch him off-guard or get some world-shaking magic that no one is invulnerable to. The latter happens, taking the form of the force of the Interconnection spell, which throws Sang-Drax deep into The Vortex.
Devil May Cry 4 has the Gladius demons that can freely shift between a sword form and a flying reptile form.
The main characters from Digital Devil Saga have the power to transform into powerful demons, but at the cost of gaining an insatiable hunger for human flesh. Trying to resist this hunger results in the human mind being eroded, and eventually overwritten by the personality of the mythological being the demon represents. All enemies you fight are also on the same boat. Gameplay-wise, characters start every battle in demon form unless they were ambushed, and a turn must be spent to switch forms. Human forms lack all the powers and elemental resistances demons have, but they're immune to Expel spells, and attack with guns that certain enemies are weak to. The second game also has the Berserk Mode, which is a partial transformation that randomly occurs at certain Solar Noise phases.
Disgaea 4 show that many humanoid demons take their form as a matter of convenience and that their true forms look quite a bit differently, though it's unclear if this applies to characters from earlier games. Hugo is a reaper that looks like a muscular old man, but can transform multiple time when he's at full power, though we only see him turn into a normal reaper. Valvatorez is a giant black dragon, which he displays in several skills, including one where he transforms only his arm to swipe at people. Emizel is a massive green creature that looks like a jester with a skeletal tail while Desco is really an Eldritch Abomination far larger than she appears, despite looking like a little girl in strange clothing who just happens to be able to grow tentacles.
Morrigan in Dragon Age: Origins has this power, and can teach it to other mages in the party, as well. Her mother Flemeth is even better at it. Interestingly, neither of them is able to turn into another human (or elf, dwarf, qunari, darkspawn) due to the nature of learning how to do it.
The spell Morph allows characters to shapeshift into other characters from the party to copy their skills. A few enemies, like Admirers and Float-o-copiers can use the spell to shapeshift into the player characters, giving you a change to see their battle sprites. The spell Puff! allows a character to transform into a fire-breathing dragon, while Kaclang turns the entire party into steel statues, making them immune to damaga but unable to act.
Dragon Quest III: The Mod Rod lets you randomly change to different forms. Including monsters. NPC's react accordingly to this. Except for faeries, who can see right through most disguises… Yet will still sell to you if you transform into a dwarf or other creature they're friendly with.
Elisa, The Hero's best friend. Thanks to her magic, she's able to take different forms, something she uses to play pranks... and make a Heroic Sacrifice via Death Faked for You.
Maya's Puff spell lets her transform into a fire-breathing dragon.
Dragon Quest V: Madchen learns Puff!/BeDragon, letting her transform into a fire-breathing dragon during battle.
Dragon Quest VI has Amos, if he is given the Seeds of Reasoning to control his monster transformation.
This is a trait of the Daedric Princes. They are not bound to any one physical form and can manifest in whatever form they wish. Most stick to one humanoid form when dealing with mortals, though a few are known to change the gender of that form between appearances.
Hircine, the Daedric Prince of the Hunt, possesses this ability like all Daedric Princes, but he has several different forms which he uses to present himself to mortals, each of which represents a different aspect of his. These include "The Hunter" (also known as Guile), the "Quick Fox" (also known as Speed, and sometimes taking the form of a Savage Wolf instead), the "Mighty Bear" (also known as Strength), the "Manbeast", and the "Great Stag".
EXTRAPOWER: Giant Fist: Blackberry is able to transform herself into a small mouse, both as her version of combat dodging and for infiltration. When in mouse form, she's even dark blue like her normal hair colour and has mouse-sized versions of her hair decorations.
Jenova from Final Fantasy VII (and anything with its cells) is essentially a semi-sentient viral colony that can read people's minds and assume the form, voice, and memories it finds there. The Jenova-infused protagonist, Cloud Strife, is a coalescence of himself, his best friend and his girlfriend's memories. Jenova was eventually defeated by the Cetra, stuck in the half-gnarled appearance of the last person it tried to imitate.
Liquid Flame, a fire-type boss from Final Fantasy V has 3 forms: a human, a hand, and a flame tornado.
Final Fantasy IV and Final Fantasy V feature an enemy called Metamorpha, a wizard who can shapeshift into other enemies, including Summons.
The Laguz from the Fire Emblem: Path of Radiance and Fire Emblem: Radiant Dawn are able to transform into their respective animals (be they beast, bird or dragon) for offensive purposes, so long as the on-screen laguz transformation gauge is full (in Path of Radiance), or has any points in it at all (in Radiant Dawn). They are forced back into their humanoid form once the gauge depletes. The rulers of the tribes can stay in their animal forms indefinitely.
The Manaketes of the rest of the series can transform into dragons, albeit with the use of a Dragonstone. It is also possible for them to lose their ability to transform, as shown by Gotoh and Xane, although Xane makes up for it by virtue of being able to transform into anything except a dragon.
Fire Emblem Fates has the Nohr-exclusive Wolfskin (who can transform into ogre-like werewolves) and the Hoshido-exclusive Kitsune (basically, well, Kitsune). The player avatar, a half-dragon, and their child Kana can also transform into a dragon.
God of War Ragnarök expands Atreus' role considerably, allowing him to be played in the foreground in addition to serving as Kratos' Assist Character. This is his version of Spartan Rage, transforming into the form of his pet wolf, Fenrir. Atreus doesn't gain this ability until he overcomes some initial Power Incontinence, per usual for powers as a puberty metaphor.
In I Was a Teenage Exocolonist, Sym can reshape his form into any living organism, even modify their parts, to better understand their biological functions. He usually turns into a tree to hide away from other Gardeners.
This is the central mechanic of Jimmy and the Pulsating Mass. Jimmy is such an empathetic person that by imagining what it's like to be certain enemies, he can transform into them, altering his stats and giving him different abilities.
Orochi, Magaki and Saiki from The King of Fighters series. They shift their form when in combat.
Kirby's most well-known characteristic is the ability to copy the abilities of his foes, changing his appearance in the process.
Only a few copy abilities (Wheel, U.F.O.), since generally it's just Power Copying. Though Kirby's Epic Yarn seems to focus more on this instead. And non-platformers often feature him in a ball shape, if that counts. Kirby and the Rainbow Curse appears to be a combination of both.
Crazen of Lusternia uses this ability to extremely creepy effect, as Krokano can attest:
I roared and tried to fling Thalrinda from me, but her arms locked around my neck, becoming a loop of flesh that tightened around me like a noose. Her mouth pressed up against my face as she leaned forward, her lips scraping against my eyelids. Her tongue split in two and plunged into my eye sockets. Any semblance of form was all but gone, now, melted away like wax: revealing itself to be a the tip of one of Crazen's huge tendrils.
The Darloks of the Master of Orion series have this trait, which manifests as a bonus to espionage.
Played straight as the main gimmick of Mega Man ZX Advent, with Model A being able to take on the shapes of previously defeated bosses.
Samus in the Metroid series gets to transform into a "Morph Ball" form to fit into tight spaces, set bombs, activate switches, and even roll up magnetic walls. In Metroid Prime: Hunters, other bounty hunters appear, who have their own "alt forms". Gandrayda in Metroid Prime 3: Corruption is a more traditional version.
Shang Tsung in the Mortal Kombat series has the ability to shapeshift. In the first game during his battle, he would change randomly into any of the characters. In the second game, he could only transform into Kintaro as a fatality. The third game (and its editions) marks the only time he could transform into any of the characters as a playable feature (though it took loading time). While it was limited gameplay wise, it's implied storywise that he could transform into anyone he wishes to.
The film limits his ability to only be able to morph into someone whose soul he absorbed. Then again, we only really see him do it twice. First, when he pretends to be Johnny Cage's sensei (presumably, he killed the real one), and at the end, when he turns into Liu Kang's brother, whom he kills at the start of the film.
The title character in the PlayStation game Muppet Monster Adventure is Kermit's nephew Robin. In it, Kermit, Miss Piggy, Fozzi, Gonzo and Clifford have been turned into the following monsters: Frankenstein-like thing, Bride Of Frankenstein-like thing, werebear, vampire, and muck monster, and in the game, you can get the powers of those monsters after collecting amulet pieces — Robin takes on a form similar to that of the monster his powers are from.
Polymorphing in NetHack is one of the most complex and difficult aspects of the game, that can lead to major benefits if done well. A character has several ways to self-polymorph, such as a wand, spellbook, ring, trap, potion, eating a polymorphing monster, and more. Most of these are uncontrolled without some form of polymorph control, such as a ring or an intrinsic. Incidentally, polymorph control also lets you choose whether or not to accept shapeshifting due to lycanthropy. Polymorphing can be very useful or detrimental, depending on if the new form destroys armor or if it can handle what the character is already carrying. (Weirdly, Magic Pants is only played straight with the character's pants, as there are none equippable in game and there are ways the player should die if they aren't wearing pants.)
Revenants in Nexus Clash are a mashup of vampire and werewolf tropes and are implied to be the common origin of both in-universe. Most of their powers revolve around turning into a whole collection of different dangerous forms depending on the needs of the battle.
Nobody Saves the World: At the start of the game, the player character obtains a magic wand that gives them the ability to shapeshift into a variety of forms, from humans to animals to monsters, each with their own abilities, strengths and weaknesses.
In the game, Ditto can only transform into whichever Pokémon it is facing at the time with a purple tint (this was later removed in newer games, where the transformed Ditto was simply a lighter tint of normal Pokémon). In the anime, they can transform into all different things including Pokémon, but some of them keep the creepy looking face of the original. The Mythical Pokémon Mew also possesses this ability both in the games and shown in one of the movies.
Zoroark, being based on a kitsune, can imitate the appearance of other Pokemon, but this is merely an Illusion and not a true transfiguration.
[PROTOTYPE] has Alex Mercer, whose main power is this and includes shifting his body into weapons or armor — and becoming people he has absorbed, complete with their memories and skills.
The Mimics from Prey (2017) have the ability to transform into inanimate objects. Their advanced variants supposedly have the ability to copy complex machinery like turrets and operators, and Morgan can learn to do the same by installing Typhon neuromods. In The Stinger, the Player Character transforms into a human form when taking Alex's hand; it's unclear whether this is something all Typhon can do (as this is the only time we ever see one do it) or if it's a side effect of the human neuromods that Alex installed in it.
Primal has a female main character who can shapeshift into unique monster-like forms.
The Quest for Glory series has Leopardmen and Gypsies (who turn into wolves) in games 3 and 4 respectively. Unfortunately for the latter, the easily spooked townsfolk buy into all the old Werewolf legends, which is what sets off the first big plot event of the game.
In Roots of Pacha, Owl and Monkey give you their totem powers after completing their challenges. They allow you to transform into them on designated platforms so you can fly around and hop on floating pillars, respectively.
Cucuvea, on top of being an immensely powerful White Mage, can transform herself into an owl — and is commonly known as "the owl" for this very reason. In fact, she rarely leaves her secluded home except in owl form, and the only way you can actually find her to begin with is by following the owl back to her den.
Elder vampires can transform themselves into bats, though they usually only do so in dire emergencies, usually in order to escape being staked by the players. Naturally, the key goal is to catch up and kill them before they can recover their health.
The mysterious Dark Woods Horror is eventually revealed to be a form of this: basically, the Orochi Group have been kidnapping children and infecting them with Lycanthropy, believing that werewolves only become wolves due to the subconscious influence of thousands of years of folklore; unfamiliar with the legends, children would be free of this tendency. As a result, the Dark Woods Horror is able to shapeshift into a form fitting his own anger and rage. For good measure, unlike werewolves, he really does transform back into his old self at the moment of death.
The mysterious Faust Capital CEO is able to take on humanoid forms at well, being initially encountered in the form of a small child. He's really a Jinn known as Mephistopheles.
ShadowCaster: Via arrangements with beings from other worlds, the protagonist's people can exchange forms with those beings. There are six such available to the player, gained over the course of the game. The main villain, being of the same people as the player-character, evinces the same power, with their own set of forms, during the final battle.
The Harmonixers from the Shadow Hearts series have this as their main ability. Yuri, from the first and second games, is the most versatile, being able to take at least 20 forms. Shania's more oriented towards fanservice.
Shape Shift Shawn, as the name implies, features voluntary shapeshifting as the game's primary mechanic. The main character, Shawn Maxwell, discovers an underground world populated by "Muties," which are fairy-like creatures of different colors. Each color of Mutie has the ability to transform Shawn into a different form. Throughout the game, the player has the ability to transform Shawn into a fire-breathingdragon (red Muties), a balloon (blue Muties), an ogre (yellow Muties), or a slime creature (green Muties).
Also in The Simpsons Game, Homer can transform into Homer Ball, Gummi Homer, and Helium Homer. A few of the other family members have transformations too, including Bart.
So Many Me: The Mes have the power to change into things that are required to bypass obstavles in the game. The first thing they can turn into is floating blocks that Filo can stick to.
Inklings can transform between a human form capable of using weapons and a squid form that can hide in and rapidly swim through ink. They share this ability with their Octarian counterparts, Octolings, who turn into octopuses instead.
In a blink-and-you'll-miss-it example, Sheldon will quickly transform from his hermit crab form to his humanoid one whenever you enter his shop.
In SpongeBob's Truth or Square, SpongeBob turns into several objects in order to attack; he can become a spatula to slam his foes (or a hammer with the SpongeBuff or Patrick powerups), a ship wheel or fan blades to spin and hit all around him, a pair of karate gloves for Sandy to wield while also spinning, a cannon to shoot projectiles, or a clarinet which Squidward uses to spam Spread Shots.
The Paper Mario series also has shapeshifter characters: Duplighosts from Paper Mario 64, including Doopliss from Paper Mario: The Thousand-Year Door (who can also apparently steal the body/physical appearance of another character, leaving them a blank shadow, and Mimi from Super Paper Mario who can take the form of various characters as well as become some horrifying Thing-esque spider monster.
Tanoombas in the first two Mario & Luigi games are Goombas with tanuki tails that attack by taking the forms of Mario and Luigi in the first and a Thwomp in the second.
SNES video game Super Morph featured a ball-like thing with shapeshifting powers: main forms include a raincloud and a few others.
The Spy from Team Fortress 2 has a device that allows him to disguise as any playable character on any team. Some items like the Your Eternal Reward put a spin on this ability, forcing you to require and consume full cloaking energy for normal disguising but allowing you to backstab someone and almost instantly disguise as them.
Tekken has quite a few including Ogre. Also in Tekken Tag Tournament Kazuya can turn into Devil.
Mimit from Temtem was created to be able to breed with any species, and has a "genomic reservoir" in its tail that allows it to transform. In battle, Mimit with the Landing Transmog trait transform into the next Temtem in clockwise order when it enters the battle, while ones with Striking Transmog transform into any Temtem they hit with a physical move.
Mamizou Futatsuiwa, what with being a Tanuki and all. She even takes the form of Reimu for one of her Spell Cards.
This applies to the other tanuki as well (and the ones we've seen have fewer give-aways than Mamizou), they just don't have names. Additionally, Orin is capable of reverse-animorphism, taking a human-like form in addition to her natural cat body. The same is believed to apply to the other beast type youkai, though it hasn't been confirmed.
The Druids of Tree of Savior can shapeshift into a targeted plant, insect, or animal, as well as return to the form of one they targeted previously, giving them some adaptability.
All the Fables who wear (and are freely able to enable/disable) Glamours in The Wolf Among Us. This includes Jersey, Grendel and Holly. Note that some characters, Beast and Bigby, have transformational abilities that are innate and aren't the result of glamours.
A Very Long Rope to the Top of the Sky: When fighting a Shapeshifter, it has a move that involves it saying "I can be anything I want!" implying that their shapeshifting is voluntary.
The Wolf and the Waves: The player character can shift between human, wolf, and ghost form. At the end of the game, they craft a potion that transforms them into a bird.
Druids in the series are pretty much defined by this ability. The player version in World of Warcraft can change into a bear, a panther/lion, a cheetah (for faster movement), a sea lion, or a bird, as well as an owlbear or a treant if properly specialized. Non-playable druids can sometimes take other forms as well, such as a serpent.
The Shaman class also has the ability to shapeshift into a wolf for faster movement, while Warlocks can temporarily turn into a demon. Lesser forms include the dwarven racial Stoneform, the Death Knight Lichborne ability (which grants them immunity to many status effects) and the Priest abilities Shadowform and Dispersion.
Shapeshifting into a humanoid form (usually human or elf) is a common ability among dragons in the series. Some demons can do this too.
Player-character worgen have the ability to revert to their previous human forms after a certain quest. However, if they're ever in combat, they automatically shift into worgen form.
Draconic NPCs of the major dragonflights have this ability, though a number of them such as Alexstrasza and Ysera still have horns in humanoid form.
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