Name: PDFtk Server
Open Source: yes
Description: "PDFtk Server is our command-line tool for working with PDFs. It is commonly used for client-side scripting or server-side processing of PDFs."
As far as I know, there is only poppler-utils (pdfseparate, pdfunite) that is able to split and merge pdf documents in the repositories. PDFtk would be helpful for many, I guess.