Hello @Seed_Store_Lady. With our updated experience, we do not have the ability to favorite templates at this time. I will put in feedback to our developers with this request. However, you are able to save a a sent email as a template!
1. Open your sent email. Click on the Actions dropdown menu and then Save as Template
2. You will now see this message
3. Go to Campaigns and click Create
4. Select Send an Email
5. There will be a tab that says "Saved Templates" and you will find your saved email there to select.
Hope this helps!