Mailbutler

Mailbutler adds a wide range of features to Apple Mail while working in its native interface: Send Later: Write emails now, send them later Tracker: See what happens to your emails after they are sent Cloud Upload: Upload email attachments to the cloud to keep your messages feather-light Undo Send: Retract messages after having pressed "Send" Emails to Notes: Easily create notes (e.g. in Evernote) from your emails Attachment Reminder: Never forget to attach files to your emails again Signatures: Appear more professional by using a beautiful email signature.

Limitations:

Essential features only