No need to go anywhere :)

  >> words: keys-of system/words
  >> types: collect [forall words [if datatype! = type? get/any words/1 [keep words/1]]]
  >> probe types
  [datatype! unset! none! logic! block! paren! string! file! url! char! integer! float! word! set-word! lit-word! get-word! refinement! issue! native! action! op! function! path! lit-path! set-path! get-path! routine! bitset! point! object! typeset! error! vector! hash! pair! percent! tuple! map! binary! time! tag! email! handle! image! event!]

The Red website has it somewhere, but they're focusing on the Lang and not the site at the moment, so it might be hard to find. I think the Rebol website (successor language that is mostly compatible although interpreted only) should have a lot of those.

here is a list of datatypes from REBOL days, Red is probably mostly there

http://compsci.ca/v3/viewtopic.php?t=17726