ConvertKit
ConvertKit is an email marketing platform that helps you send customized emails to your customers. It helps you send well-timed and accurately targeted email content to your subscribers.
By integrating your forms.app and ConvertKit accounts, you can create a subscriber record and segment your customers by adding tags to your subscribers. You can also add a purchase record to your subscriber profiles.
You might also like

Assignar
Work to ensure that your projects are delivered on time and within budget.Zapier

Constant Contact
Grow your contact list using your form submissions.Zapier

Zapier

Klenty
Streamline new contacts to your emailing list from your form responses and automate your work.Zapier