There is this nice tool that will allow you to send a template to a list of users:
Custom emails gmail from list
There is a more basic version here, that does not allow to add personalized variables inside the mail or even in the subject http://www.labnol.org/software/mail-merge-with-gmail/13289/
There is another tool also from LabNol, that will allow you to track with Google Analytics that the mail has been opened or not:
This works for Android 4.4 and for earlier versions as well
Go to settings > device > application
You will see the list of all apps. Select the one you want and uncheck the tickbox “show notifications”.
You can see the example of how to remove notifications.
This works to disable Facebook notifications in Android as well. Actually it works to disable notifications for any app in Android.
I am still waiting for the Android team to create a notification center where it is possible to manage this easier from one screen, ao there is no need to hop from one to the other to uncheck the magic box.
If you search for “unread” mails you will get mails that are in all the tabs.
The search query you have to use is:
is:inbox -category:(updates OR promotions OR social OR forums) is:unread
As seen on: http://techwelkin.com/search-unread-emails-primary-tab-gmail