Apple Mail Add-ons
By default, every Mac is loaded up with a copy of Apple's email client, Mail. As far as email apps, it is fine, but it is missing a lot of features and settings that other apps have. Fortunately, with a few add-ons, you can turn Apple Mail into a pretty powerful little email client. Please read the note at the bottom of this page before proceeding.
Here is a great list of Apple Mail add-ons.
Please note: TechnoMinds is providing a list of Apple Mail add-ons. We do not know the condition of your computer, nor can we know the possible bugs a particular version of each app has. Each app has it's own compatibility requirements and some may not be free. It is up to the user to determine if his/her system is compatable or not. It is also recommended that you only try these if your computer and specifically your Mail app are running smoothly, without trouble. Most importantly, make sure sure you have an up to date backup of your computer including your Apple Mail app, your Apple Mail database and preferences. Proceed at your own risk.