things now on my photo radar:
good nikon sb-??? flash
a good slave system,
an umbrella flash slave kit
a bracket for off camera flash
flash filters...
a quantity of good cheap older / period nikon lenses
the nikon eyepiece cup
the hove magic lantern f4 book
certainly a slippery slope...
The SB-24 was the 'period' flash for the F4 but any of the later models will work up to the SB-800 ( I use the SB-800 and an SB-25). I think support for the film TTL cameras was dropped with the SB-900 and later flashes.