I have a few questions about the '.reloc' section:

1. Does this section appear only for DLLs or it is needed for PE files too?

2. What is 'fixups'? Is it a FASM keyword? I need to know all keywords for syntax highlighting.

1. not needed in PE. All PEs are located at 400000h.
2. a, yes
b, download dos distribution of FASM and parse all words in quotes ("") from documentation. Or take them from FASM sources.

1. In modern versions of Window it is needed for DLLs and drivers only, however Win32s required it for all executables (that's why PEDEMO includes '.reloc' section, as it was an example made to work also in Win32s - same with console version of fasm).

2. Yes, it's a keyword, see section 2.4.2 of the manual.
And if you need to get a list of all fasm's keywords, see file SOURCE/TABLES.INC in any fasm's distribution (there are only two other keywords, that are not listed there - these are EQU and FIX).