Blaze

In-Game Text: Powers up Fire-type moves in a pinch.

In-Depth Description: Fire-type moves have their power increased by 50% when the Pokémon’s HP falls below ⅓ of its maximum.

Like Overgrow and Torrent, Blaze is the signature ability for the Fire-type starter Pokémon. Though useful under certain circumstances, most of the Fire-type starters have much better Hidden Abilities, such as Speed Boost on Blaziken, Reckless on Emboar, and Iron Fist on Infernape.

Charizard used to make good use of this ability with a Belly Drum set and a Salac Berry to increase its Speed, but even Solar Power is a far superior ability to Blaze, granting Charizard exceptionally powerful attacks at the sacrifice of some HP.

Now that Charizard has been given two mega evolutions, Blaze is even less useful than it was before, as both of Charizards mega forms are far superior to its normal form.

Though the added power is useful if you are making a last-ditch effort at dealing some damage before going down, you are almost always better off using a different ability, if you can.

There is one Pokémon, though, that can take advantage of this ability: Infernape.  Infernape has some dedicated lead sets that equip it with Focus Sash and the moves Stealth Rock, Fake Out, Overheat, and Close Combat.  Once Infernape is knocked down to 1 HP because of the Focus Sash, Blaze activates and hits like a truck.

Pokémon With This Ability Available
Charmander
Charmeleon
Charizard
Cyndaquil
Quilava
Typhlosion
Torchic
Combusken
Blaziken
Chimchar
Monferno
Infernape
Tepig
Pignite
Emboar
Fennekin
Braixen
Delphox
Pansear (Hidden Ability)
Simisear (Hidden Ability)