The Visualization Toolkit (VTK) is an open-source, freely available software system for 3D computer graphics, image processing and visualization. VTK consists of a C++ class library and several interpreted interface layers including Tcl/Tk, Java, and Python.
The ReportLab Open Source PDF library is a proven industry-strength PDF generating solution, that you can use for meeting your requirements and deadlines in enterprise reporting systems.
NLTK — the Natural Language Toolkit — is a suite of open source Python modules, data and documentation for research and development in natural language processing. NLTK contains Code supporting dozens of NLP tasks, along with 40 popular Corpora and extensive Documentation including a 375-page online Book. Distributions for Windows, Mac OSX and Linux are available.