Gmail Logout Page describes that the user can now add multiple gmail accounts.

The image shown at logout page is as follows:

 The two different Gmail accounts are shown in this image below.

Right now, there is a provision to add only Gmail accounts and users will be delighted to use this feature as it will really save the login and logout actions.

It will be interesting to use this feature if any Google account addition is allowed. All in all, this feature will certainly offer fast paced account access as the user could add multiple accounts. Hence, Google should look forward and design this feature so that any type of Google account can be added so those users don’t need to logout to switch between the accounts. 

At last this attempt by Google is outstanding and we hope they will allow the users to add any type of Google accounts in future.