(Just my headcannons about everybody's favorite dancing and music genre)
(And I'll try to find good video representations, if there isn't one for everyone- I just couldn't find one)

Optimus: Beethoven. Waltz/Ballroom dancing.
As stoic and serious as he is, Optimus loves a good romantic dance. It's been a while for him though, but he does occasionally dance with people if he's cheery enough.

Ultra Magnus: Same as OP (just like how he copied eVERYTHING ABOUT OPTIMUS IN THE SHOW)

Ratchet: Doesn't dance.

Bulkhead: Jon Bovi. Rock music, though he isn't very graceful- he tries without hesitation to dance to any heavy metal or punk genre at his best with Miko.

https://youtu.be/bXsmGSnq3lE

Bumblebee: Pegboard Nerds. Techno/Electronica. He likes doing the robot occasionally if the beat goes well.
(A song by Pegboard Nerds)

https://youtu.be/tS3HPXCxJUw

https://youtu.be/UIPH4ikWLKs

Arcee: Broadway Musicals. She doesn't dance, but she does like the music. Same goes for Jack.

https://youtu.be/BlDmbRChass

https://youtu.be/gYb9sRLUDyM

Smokescreen: Basically a mix of Bulkhead and Bumblebee.

Wheeljack: Same as Bulkhead.

Mercy: Unknown. She doesn't dance- but she enjoys paranormal songs. (Accurate representation of one of my sister's favorite genre(I swear she's not emo, she's happy and bright- she just likes these)

https://youtu.be/f_AyjjBAV8c

Nocturne: Unknown. Shuffling, she enjoys the ecstatic feel to it. This also goes for Nicole.

https://youtu.be/zJD7PgbthdE

That's it. Tell me if I missed anybody. Other than the Decepticons, of course.

Xx_PRIME_xX