Symantec Workflow Manager has a number of Plugins available from install.
The idea here is to document each plugin, much like the Components.
Three others are from within the Workflow Manager home page under the Local folder.
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The Community listed ones are below
Documentation
Symantec™ Workflow 8.1 User Guide https://support.symantec.com/en_US/article.DOC9625.html
Symantec™ Workflow 8.1 Component Developer Guide https://support.symantec.com/en_US/article.DOC9626.html
And a set of Articles you can follow