Adobe InDesign Plug-ins
These companies offer software plug-ins and add-ons that expand the capabilities of Adobe InDesign software.
Em Software InData
Plug-ins include InData, InCatalog, and InFlow for managing database and spreadsheet data in Adobe InDesign. They also do QuarkXPress XTensions.
Gluon
Cropster ID adds many cropmark options. ProScale ID] is a resizing tool. Other InDesign plug-ins handle slugs and document splitting.
InDesign Magazine
In addition to tutorials and industry news they provide reviews of plug-ins and other add-ons for Adobe InDesign.
InDesignSecrets.com
Learn about the latest plug-ins, including lots of free plug-ins and scripts for Adobe InDesign.
WoodWing Smart Plug-ins
Smart Styles and Smart Layout add flexibility and features for users doing complex layouts such as magazines, newspapers, catalogs, and more. Free demos available for these and other InDesign plug-ins.