How does one submit a new genre?

Title explains the question. I was looking for Space Shooter, but it wasn't on there.

Thats a theme, not a genre

No, it's definitely a genre. Maybe sub-genre. Which makes it inapplicable, I guess, but that genre list is a little lacking.

Is there even a place where we can suggest a new one?

I use the Shooter genre for space shooters.