Sandcastle!

Doxygen is a tool for generating documentation from annotated C++ sources, as well as other popular programming languages like C, Objective-C, C#, PHP, Java, Python, IDL (CORBA, Microsoft, and UNO/OpenOffice flavors), Fortran, VHDL, Tcl, and to some extent D.

Slate - beautiful static documentation for your API.

sharpDox is a documentation tool to create c# code documentation of any type. The tool creates a model of a given c# solution and passes it to the registered export plugins. The plugins transform the model to a defined output. sharpDox comes with a chm & html export plugin which demonstrate the possibilities of the tool.

DoxyS is a code documentation tool for C++/C. DoxyS strives to yield a very professional looking output, presenting the the code in a structured easy to navigate set of HTML pages. Easy to use: Just navigate to the root of your code directory and type doxys.

PHP documentation generator based on docblock parsing.

NDoc generates class library documentation from .NET assemblies and the XML documentation files generated by the C# compiler (or with an add-on tool for VB.NET).

Natural Docs is an open-source documentation generator for multiple programming languages. You document your code in a natural syntax that reads like plain English. Natural Docs then scans your code and builds high-quality HTML documentation from it.

CppDoc generates HTML documentation for C++ classes, based on your source code and special comments embedded within it. It can produce output that is very similar to the output of Javadoc, and it supports Javadoc tags such as @see, @return , etc. The documentation comments are optional; if you leave them out, CppDoc will still generate a full set of documentation based on class relationships and hierarchy.

Javadoc is a tool from Sun Microsystems for generating API documentation in HTML format from doc comments in source code.

Asciidoclet is a Javadoc Doclet based on Asciidoctor that lets you write Javadoc in the AsciiDoc syntax.

Doc-O-Matic is a software source code documentation and Help authoring tool. It takes source code and comments, adds conceptual topics and external input and produces documentation from it. With its single-source approach it generates many different kinds of output from a single documentation base.

EDoC++ is a C++ source analysis tool designed to identify problems associated with the use of exceptions in C++ code. Additionally EDoC++ can be used to generate detailed documentation

ForgeDoc is a class library documentation generator for .NET assemblies. It can create MSDN-style API reference documentations in HTML and CHM output formats. It completely supports the latest .NET Framework with proper syntax generation for C#, VB.NET and C++ languages.

LDoc is Lua documentation generator intended to be compatible with LuaDoc and thus follows the pattern set by the various Doc tools:

LuaDoc is a documentation generator tool for Lua source code. It parses the declarations and documentation comments in a set of Lua source files and produces a set of XHTML pages describing the commented declarations and functions.