What are the main categories of Science Fiction and Fantasy?

I’m working on creating a database of SFF, and one of the pieces is categorizing works. Trying to figure out what the categories ought to be…

Military SF

Space Opera

Planetary Romance (is this used? how is it different from Space Opera)

Urban Fantasy

Contemporary Fantasy (is this used? how is it different from Urban Fantasy?)

Epic Fantasy

Now my brain is drawing a blank. Maybe I’ll have to go browse Amazon.

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