FileOpen Systems Inc.
- A plugin to Adobe Acrobat that helps ensure that a digital publication is not redistributed or uploaded to another website.
- http://www.fileopen.com/

Mapsoft Computer Services
- Details of the Acrobat and PageMaker Plug-ins, and custom development services available.
- http://www.mapsoft.com/

IntelliPDF
- Adds Bates Stamps to PDF documents.
- http://www.intellipdf.com

Evermap
- Provide AutoSplit plug-in for Adobe Acrobat, used for document splitting and page extraction. Includes news, downloads, support pages, and company profile.
- http://www.evermap.com/

Datafarm Inc.
- Developers of Acrobat Plug-ins and other PDF tools.
- http://www.datafarminc.com/

LineType Software, Inc.
- LineScale plug-in for Acrobat and Acrobat Reader is the premier distance and area measuring tool for PDF files, offering unique features in an easy-to-use interface. Electronic document solutions and consulting services for architects, engineers and contr
- http://www.linetype.com/

PDFtoALL
- Plug-in that converts PDF files to text, HTML, BMP, JPG and PNG. Information and demonstrations available for download.
- http://www.pdftoall.com/

LD-Converter
- Plug-in for Acrobat that converts PDF to text, HTML, bmp and jpg. Software descriptions, screenshots, FAQs, demo downloads, and contact details.
- http://www.pdftoall.com/pdf%20magic.htm

Quite Software
- Developers of plugins, such as Quite A Box Of Tricks, Quite Imposing, and Quite RGBGone.
- http://www.quite.com/

PDF Snake
- Adobe Acrobat plugin that adds imposition, scaling, watermarking and other features.
- http://www.pdfsnake.com/

Merlin Open Systems
- Developer of cross-platform Adobe Acrobat plugins.
- http://www.merlin-os.co.uk/