XpressDox - XpressDox Desktop for Microsoft® Office Word is an affordable document assembly system.
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
docassemble - docassemble is a free, open-source expert system for guided interviews and document assembly.
SmallDevTools - Handy developer tools with a delightful interface
HotDocs - Template-driven, automated document & form assembly software
GitHub Student Developer Pack - The best developer tools, free for students.