You noticed that there are form actions missing from the Form Actions dropdown. The following options should be missing:
An example of this dropdown may appear as:
This is due to the form having been created using an outdated version of the Marketo Form Editor. You may want to consider re-creating this form with the current Marketo Form Editor, and archiving the outdated form.
Keep in mind that if you archive the form, you will want to reference the new form in smart lists and smart campaigns.