The automation tool that would effectively achieve the goal of adding prospects to a list after they submit a form, but not retroactively applying actions to prospects that have already filled out the form, is a completion action. Completion actions are actions that are triggered when a prospect completes a specific activity, such as submitting a form, clicking a link, or opening an email. Completion actions are executed in real time and only affect the prospects who complete the activity after the action is set up. Segmentation rules, dynamic lists, and automation rules are not suitable for this goal, as they are either retroactive, recurring, or based on criteria other than a specific activity. References Completion Actions Overview