Headers are only created for classes we need, and only methods that we use are added to them. This is due to the large number of classes and methods that are broken in class dumps - this way, we manually set up the headers and they are guaranteed to work.
Feel free to use these (git clone git://github.com/hbang/headers.git $THEOS/include - if you have an existing$THEOS/include directory, rename it) and add on to them.