kengher

Broadcast simple, important alerts across your multisite network. Also great for single sites.
Features of Site Alert: 
* Display alert(s) in the Homepage with option to show in all pages of a site. 
* Native WordPress WYSIWYG message creation box for simplicity with media support. 
* Choice of hardcoded at the different parts of the page, or make it a pop-up modal. 
* Indicate different priority levels (colors) and icons. 
* Set a date range to publish/unpublish the alert.
Features as a Network Admin 
* Show alert across all all sites in your multisite network. 
* Exclude alert(s) from certain sites. 
* Site Groups manager to provide easier bulk exclusions.

Super Simple Site Alert

Broadcast simple, important alerts across your multisite network. Also great for single sites.

PasqualePuzio

This plugin sends an email to the administrator for each login. The goal of this plugin is to improve the security of your website and keep under control all the accesses to your website.
You can customize the email template and exclude from notifications the admin access.
For further information and support contact me visiting my website or the official plugin support page: 
– <a href="http://www.pasqualepuzio.it" rel="nofollow ugc">WordPress Consultant & Specialist</a> 
– <a href="http://www.pasqualepuzio.it/plugin-wordpress/login-alert/" rel="nofollow ugc">WordPress Login Alert Plugin/a></a>

Login Alert

This plugin sends an email to the administrator for each login.

Super Simple Site Alert vs Login Alert