We wanted a full drag-and-drop solution for the post Call-to-Action, so you can freely add whatever you want in there (e.g. a Form, a button, etc) and create custom layouts for your CTA section. So there are three options in the Design Tools:
When you edit your post you can select one of the options or Nothing:
IMPORTANT: Once you selected your option and saved the changes please make sure to force a browser reload (reload the entire page), so HubSpot can update its editor for the new option, otherwise they won't appear as editable modules in the editor.