You can share email templates between users within your team.
This requires a Team subscription, which allows you to have up to 10 users. It costs $480 / year and can be purchased using the following link: https://app.gmergeplus.com/account/billing
These templates are accessible from the Mail Merge / Email template section of the add-on as well as the G Merge Plus application.
From the Add-on:
From the sidebar, under Mail Merge > Email template, click on Select/Create, then click on Template Library.
From the Application:
Click on the Templates tab near the top of the page, select any template of your choice, then click on the options menu (3 dots), and click Edit.
Once the template is opened, click on the save button (disk icon) to save the template, and tick on the box that says "Shared" in order to share it with team members.