comment-pln – Comment macros for use in Plain TeX
Defines macros \comment and \endcomment such that everything between the two is ignored.
Maybe you are interested in the following packages as well.
- optional: Facilitate optional printing of parts of a document
- codesection: Provides an environment that may be conditionally included
- tagging: Document configuration with tags
- ifthenx: Extra tests for \ifthenelse