The user can transform their bodies or weapons into their true forms if sealed, restrained, or just not activated, unlocking their dormant power in order to drastically increase their regular power. All their original abilities are increased along with gaining new abilities to their full power.
Komamura and Kokujō Tengen Myō'ō: Dangai Jōe's (Bleach) true forms.
Lille Barro (Bleach) in the true form of his Jilliel.
White Raven is Raven's (DC Comics) most primal, significant, and powerful version, mostly shown as a symbol of her highest hidden power and her inner purity against the consuming evil of her father
Darkseid's (DC Comics) true spiritual form.
Ceresmon (Digimon) normally takes the form of an enormous, bird-shaped living forest...
...and rarely shows her true, weaker form.
Kid Buu (Dragon Ball Z) is a Pure Majin, the true form of Majin Buu.
Kamen Rider Kiva (Emperor Form)
Like must others Etherious Demons, Mard Geer (Fairy Tail) is able to transform into his true Etherious Form.
Jackal's Etherious Form (Fairy Tail)
Doriate's Etherious Form (Fairy Tail)
Franmalth's Etherious Form (Fairy Tail)
Ezel's Etherious Form (Fairy Tail) Slash Attack Mode.
Kyouka's Etherious Form (Fairy Tail)
Torafusa's Etherious Form (Fairy Tail)
Tempesta's Etherious Form (Fairy Tail)
Seliah's Etherious Form (Fairy Tail)
Envy (Fullmetal Alchemist) has two true forms: the monstrous reptilian form when empowered by the souls of the population of Xerxes (above), and the helpless little lizard form when most of his core is damaged (below).
Sol Badguy (Guilty Gear) in his true form, Dragon Install.
When all of Alucard's (Hellsing) limiters are released, he takes on his true form, the infamous lord of vampires known as Dracula.
Krishna (Hindu Mythology) revealing Vishvarupa/God-Form, to Arjuna who's unable to bear it (Baghavad Gita)
Krebskulm (How Not to Summon a Demon Lord) in her true Demon Lord form.
Sora (Kingdom Hearts) in his final Drive form.
Marluxia's (Kingdom Hearts) final form.
Link's Master Sword (Legend of Zelda) in it's true form after being blessed by Hylia's mortal form, Zelda.
The Archfiend Vazdah (Ninja Gaiden II) in his true form.
Orochimaru's (Naruto) true form.
When granted access to Six Paths Chakra by the Sage of Six Paths, Naruto Uzumaki (Naruto) can access a transcended version of his Sage Mode…
…and access an even greater version of the Six Paths Sage Mode when he mixes his Sage Chakra with the Chakra he draws in from the Kurama the Nine-Tailed Fox.
Whenever Ryu Hayabusa (Ninja Gaiden series) places the Eye of the Dragon into his Dragon Sword, it becomes the True Dragon sword. In this state, the blade brims with the power of the 12 Divine Dragons and becomes a weapons of immense power.
Hoopa (Pokémon) in its true unbound form.
Zygarde (Pokémon) in its true form with 100% of its cells.
Groudon and Kyogre (Pokémon), in their original, "Primal" forms.
Ultra Necrozma (Pokémon) is the true, original form of Necrozma.