Eragon.
There isn't a Harry Potter character whose name begins with Gan.
Alvin
Elmur Fudd.
Ulysses
Kitara from Avatar
Quick-draw McGraw
· Mighty Mouse
Hong Kong Phooey Homer Simpson
In Holes, Stanley Yelnats is the character with a palindromic name. (It is spelled the same when read either forward or backward.)
Iago - Disney's Aladdin
Metamorphosis written by Franz Kafka
Yes, for example there is Q from Star Trek, and James Qwilleran from the 'Cat who...' books of Lilian Jackson Braun. --- If you are thinking about book characters, there's Quint from the Edge Chronicles series (does that help?)