TimeToSignUp now features a way to see all TimeToSignUp sheet participants and the items for which they signed up.
The Participant Summary shows the names/info of all participants who signed up (and the items for which they signed up) on all of your TimeToSignUp sheets. (This does not include registration forms due to the variety of fields that forms have.)
Also part of the Participant Summary is the ability to search for participants by name or email address.