We created a campaign that has a fill form for an event and but did not set-up a smart list to capture the data from the form. Is there a way to capture data that was filled out in the form to create a smart list?
What you can do is create the smart list and pull in the filter "Filled out form" and select the specific form. In the "People" tab of the smart list, you can create a new view and bring in every field on the form as a column in the view to show what value each person has. If you only wanted to see specific people that have a certain value for a specific form question, you can bring in that filter into the smart list.
Make a note that the current value for a field does not necessarily mean that value was chosen on the form. For example, John Smith fills out the form last week and answers "Blue" to a form question asking his favorite color. Afterwards, that value of "Blue" can be overwritten by another form fill, a smart campaign flow, etc.