The user can release and surround themselves in/with fire for defensive and/or offensive purposes, possibly becoming almost untouchable and granting them various abilities/attacks. The aura may also give the user enhanced physical capabilities such as speed, strength and durability.
Ultimate Kevin (Ben 10: Ultimate Alien) possesses Alan Albright and Heatblast' fire aura.
Alan Albright (Ben 10)
Hot Streak (DC Comics) flying with an aura of fire.
Pikkon's (Dragon Ball Z) Burning Shoot technique surrounds him in an aura of fire, empowering his attacks enough to easily overpower Perfect Cell.
Natsu Dragneel (Fairy Tail) surrounding himself with fire.
An Excandesco (Grimm)
Sol Badguy's (Guilty Gear) flame aura.
Liz Sherman (Hellboy) surrounded by blue flames.
Halloween (Marchen Awakens Romance) can create an aura of fire with his power.
Johnny Storm/Human Torch (Marvel Comics)
Whenever enraged or consumed by "ero" power, Vinsmoke Sanji (One Piece) emits an intense fiery aura of passion.
Whenever a Fire-type Pokémon with the ability "Blaze" like Blaziken (Pokémon) becomes too weak to fight, their ability allows them to generate a fiery aura around them to increase the effect of their attacks.
Yang Xiao Long (RWBY) demonstrates.
SCP-457 - Burning Man (SCP Foundation) has fire surrounding his entire body.
Kyo (SNK) can surround himself in fire.
Burning Blaze (Sonic the Hedgehog)
Darkspine Sonic (Sonic the Hedgehog) is perpetually surrounded by a fiery aura.
Bravenwolf Tenkai Firestorm (Tenkai Knights) powers himself with an aura of fire to attack Slyger.
Zeru (Yu Yu Hakusho) activating a flaming aura to intimidate Team Urameshi.
Hiei (Yu Yu Hakusho) surrounding himself in the Flames of the Underworld.