SimpleGMAIL is a Chrome add-on developed by cmondary that aims to simplify the interface of Gmail. With just a few CSS tweaks, this add-on provides a minimalistic and uncluttered look to your Gmail experience.

The key features of SimpleGMAIL include the addition of favicons for senders, shortening of labels to their last expression, hiding the Gmail logo, hiding the text in the search bar, fading out the search bar buttons, centering the mail list and content, centering the first and second-level menus, improving the readability of the mail list, and fading out various settings buttons.

Please note that SimpleGMAIL is the developer's first extension and may have room for improvement.