The URL that a subscriber clicked on (for click triggers)
The answer to a survey question (for survey triggers)
A subscriber's paid subscription price
A subscriber's email address
The number of clicks or opens a subscriber has had. (Note that this is the total number of clicks or opens a subscriber has had, not the number of clicks or opens for a specific email.)
The date at which a subscriber confirmed their subscription
Note that this filter is evaluated at the time that the trigger fires.