J

Jackpot,

Autobot Actionmaster. His weapon transforms into a bird.

Jazz,

Autobot Actionmaster. His weapon transforms into some sort of skate board.

Jazz,

Autobot. Transforms into a car. He is one of the Pretender Classics.

Jazz,

Autobot. Transforms into a car. He is one of the Autobot Vehicles.

Jazz,

Autobot from the second generation. Second release of Jazz. He is one of the Heroics.

Jessie,

She is Buster's girlfriend. She only appears in the comic books.

Jetfire,

Autobot Air Guardian. Transforms into a jet. He does appear in the comic books, but not in the series. In the series there is a Autobot named Skyfire, who looks very much like Jetfire. I've read a message in the newsgroup (alt.toys.transformers) once that gave a plausible explination for this difference; the Transformers were designed by two japanese firms (one of them Takara), one firm designed among others Jetfire, the Deluxe Insecticons and the Deluxe Vehicles, the other firm designed most (all?) of the other Transformers. The firm with the most influence on the series didn't want to have Transformers of it's rival in the series, so the Deluxe Insecticons and Deluxe Vehicles didn't appear. The Jetfire figure was too popular to keep out of the series, so they made a simular Transformer in it's place: Skyfire.

Jetstorm,

Autobot. Transforms into a car. He is one of the four Aquaspeeders.

Jetstorm,

Predacon. Comes from the Beast Wars. Transforms into a dragonfly.

Joyride,

Autobot. Transforms into a buggy. Hotwire transforms into his engine. He is one of the Powermasters.

Junior Headmasters,

See Headmasters.

Junkion,

Homeplanet of the Junkions.

Junkions,

Group of Autobots. They inhabit the planet Junkion, which consists out of junk. Their leader is Wreck-Gar.

Jumpstarters,

Group of two Autobots. They transform while driving. Their names are Topspin and Twintwist.