docassemble - docassemble is a free, open-source expert system for guided interviews and document assembly.
Windward Studios - Windward's solution includes a .NET or Java Engine, a set of code libraries for integrating reporting and document generation.
HotDocs - Template-driven, automated document & form assembly software
IT Glue - Proven, best practices-driven IT documentation platform packed with features designed to help you...
XpressDox - XpressDox Desktop for Microsoft® Office Word is an affordable document assembly system.
Apache Velocity - Velocity is a Java-based template engine.