Virtual Studio Technology - VST plugins

• Virtual Studio Technology (VST) is an interface for integrating software audio synthesizer and effect plugins with audio editors and hard-disk recording systems. VST and similar technologies use Digital Signal Processing to simulate traditional recording studio hardware with software.

• The VST plugin standard is the audio plugin standard created that allow any third party developers to create VST plugins for use within VST host applications. VST requires separate installations for Windows/Mac/Linux. The majority of VST plugins are available for Windows due to both Apple's proprietary Audio Unit software for OS X and the lack of information and patent encumbrances that make development difficult for Linux platforms.

Check here for vst plugins

Professional Audio Collection - Waves's Mercury

Mercury is a powerful bundle pack for pro audio. It uses for audio mastering, editing and many more. It is a pro audio package.
From time-domain effects to equalizers, from dynamics control to noise reduction, from guitar sound modeling to the sound of classic analog components, there has never been such a comprehensive collection as this.
The Mercury Collection offers more effects, more channel components, more mixdown tools, more processors than ever before in one place.