Personally a mystery would be awesome! Also mystery can also be attached to pretty much any other theme as well! :D

Sure!

I always do love good Fantasy or Sci-Fi comics.

This is quite a bit late, but I find sci-fi to be my favourite. Good luck in making the comic, whatever it might be about. :)

I'm actually a fan of sci-fi (a huge one) since in the comcs You can design all sorts of futuristic devices and it really gives You the wings to fly on! Sorry for the late comics too :D You can alwasy go with Sci-fi mystery too!
Also personally I am a fan of comics based on legends, myths or even religions - when an artist creates and entirely new point of view and their own story based on some well created ancient lore. These comics never turn our bad and give people a new view on old forgotten legends!

Sorry for being late too ^^"

Youre fine bud, Im glad alot of people are still giving their opinions and ideas, Thank you!