In Workbench 5.1's Plugin Manager you can view registered plugins and add new plugins. Plugins are shown with their publisher, version number, description (if available), and assembly name.
All Workbench plugins are contained within Dynamic Link Libraries (DLLs). You can add plugins to Workbench by selecting the desired DLL on your machine or network.
To add plugins to Workbench,
Click in the left-hand icon bar.
Click Plugins in the More pane. (If you do not see this pane, click to expand it.)
The Plugin Manager opens.
Under "Register new plugins," click the ellipsis (...) next to the Search path field.
On your machine or network, locate and open the DLL containing the plugins you want to add.
Click Add after you have chosen your directory.