Is there any place that I can find a list of reserved words in FASM?

Look at the sources.

Probably most keywords are reserved, but as I recall some pre-preprocessor directives are not. And if I remember right, you can create a macro with the name of an assembly instruction, for example a macro called mov (examples from the documentation).

If you aren't sure about something, you might want to try it and then you'll know. Try creating a macro or a variable with that name.