I have been using a MS Outlook plug-in called "Ablebits Templates" ( https://www.ablebits.com/outlook-templates-phrases/index.php ) in Outlook 365 desktop PC. But it does not work with gmail.
It has a range of "inserts" that can be put in z stored template, which then executes when you use that particular snippet (template).
The one I sorely miss in Text Blaze, is the following. It is placed inside the BODY of an Abletemplate snippet (template), and then inserts whatever-you-want into the SUBJECT LINE of any newly created email. I've found this to be a big time saver.
Can Text Blaze do this?
Here is the actual text string used in an AbleTemplate email message:
~%FILLSUBJECT= - THANKS FOR SENDING YOUR OLD RESUME. Yes I can help you - Reply from Jim The Resume Expert (Cheap Fast Resumes)