Starting with the most recent events first, I looked for available info on the web. While finding a few new clippings, I also found new, relevant info for events from the period that were already documented. For the full table of events, see World Chess Championship Zonals.
20 August 2014
Zonal Clipping Update, C16-C20
It's curious that of the ~30 events listed on Inventory of Missing Zonal Clippings, nearly all of them were played during the period 1985-2000. I've noticed this many times before: history that occurred just before or at the beginning of the Internet era is less well documented than both earlier and later history.