RazielKanos

This plguin simply adds a CSS code into your Admin Dashboard and hides most of the nagging messages telling you 
that you should activate or register other GPL 2 Plugins.
It doesn’t add any functions other than adding the CSS code, so there should be no trouble with other plugins you are using.

WP Remove Admin Register Nag

This plugin removes the reminders that you should register plugins you got by a theme for example

Comment spam is annoying, and although there are great plugins like Akismet 
to catch spam, annoying “this is best post evar” compliment spam seems to 
always wiggle through. The best way to tell if a compliment is genuine 
is to check Google to see if it’s been slathered all over the web.
Auto-querying Google is against the ToS, so this plugin just gives you 
convenient link to do the check.

O RLY

O RLY Comment Spam Search creates a quick link to make sure comments aren't spam.

WP Remove Admin Register Nag vs O RLY