The values of keynum range from 0 to 255, inclusive.
For the most part, a key's keynum corresponds to its character's ASCII value (e.g. the 'A' key is 65).
I have a list of keynames used by the bind command with their keynums which I may append at a later date.
In the meantime, if you want to know them now, you can do this:
Create a keynums.cfg with a pattern like:
bind 0x00 Key 0x00
bind 0x01 Key 0x01
...
bind 0xfe Key 0xfe
bind 0xff Key 0xff
(case matters for the hex values, and a scripting language to automate this really helps)
Back up your q3config.cfg, run Q3, "/exec keynums.cfg; bindlist; condump keynums.txt; quit"
In the file "keynums.txt" you should now have lines like:
UPARROW "Key 0x84"
There's your keynum list.