Go to KVR [[url=http://[/URL]="link removed Virtual Instruments, Virtual Effects, VST Plugins, Audio Units (AU) & RTAS Audio Plugin News, Reviews and Community - plus iOS (iPhone and iPad) and Android Audio App News Too[/]="link removed Virtual Instruments, Virtual Effects, VST Plugins, Audio Units (AU) & RTAS Audio Plugin News, Reviews and Community - plus iOS (iPhone and iPad) and Android Audio App News Too[/]

They list all available plugins, with links to the companies and downloads for free and demo plugs.

Sounds like your looking for reverbs, so do a search at KVR

Reverbs in general simulate spaces. Convolution reverbs actually reconstruct them from samples taken in real spaces.