printing event confirmations
I was going to say, "Do a search for participants (not contacts), then select PDF letter" ... but then I tried it - and there are still no event tokens.

Some work was done to add participant tokens in CRM-16734.  Although the Fix Version is 4.7.15 the related PR (PR-9038) was closed without merging.

So unfortunately I don't have a solution for you but confirming this is a known gap in functionality. It would be great if you can do anything to help progress the issue.