First you should check with the maker of the plugins and see if they have updated versions that work with photoshop cs6, as some of the older ones you list
may not work in photoshop cs6 (32 bit version) and won't work in the 64 bit version of photoshop cs6.
You would have to run the installer for most of those plugins to install in the 32 bit version of photoshop cs6.
C:\Program Files (x86)\Adobe\Adobe Photoshop CS6\Plug-ins
Some of the installers may not work for photoshop cs6.
Many people keep older versions of photoshop around for running plugins that either just won't work in newer versions, haven't been updated to be compatible with newer photoshop versions
or the plugin maker is not around anymore.
some more info: