SigPro is a plugin for Apple's Mail application that adds missing features from the way that signatures are handled and managed with your outgoing mail messages, especially if you have multiple mail accounts (and who doesn't these days). It was originally written to make up for the complete lack of signature management in versions 1.x of the program, but even 2.x is still missing some capabilities if you use several different accounts and want to share signatures between accounts.

Easy Signature Control
SigPro gives you the ability to create a signature once and use it for all accounts, even if it has account specific info in it, like your email address. Elements that can be added generically include the email address, user name & account name.
Insert Content From a Script

Using SigPro, you can insert whatever text you want into your signature by calling a script at the moment the message is created. The possibilities are endless using this capability!
Include Random Quotes

If you like to have a witty quote in your email messages, you can compile a list of them in a text file and SigPro will insert a random one for you in each new message.

Show What You are Listening To
If you like to show the world what you are listening to while working, SigPro has you covered, allowing you to display what is currently happening in iTunes. You can even customize the output based on whether music is playing, paused or stopped.

Special Content for Each Account or Alias
Each of your email accounts - and even the aliases within an account - can have separate customized content. So you can add that long disclaimer section to your work account, while having a different look and feel to your other aliases. The image to the left shows 2 distinct signature for each alias on an account.

Easily Set Signature Content
With SigPro, it’s easy to set the content of your signatures to complex mockups. If you have a webpage that you want to make into a signature, SigPro allows you to simply enter the address or open the html file and insert the contents. You can add links and images that are on the web as well.

Requirements
The latest version of Elcapitan (10.11.5) or later

Home Page - https://smallcubed.com/sp/