maybeload – Prevent reloading of files
Defines a command \thisfileis, which will become \endinput if it's called for a second or subsequent time with a particular file name.
Maybe you are interested in the following packages as well.
- rcs-pln: RCS data in Plain TeX documents
- automagic: Automagic numbering in Plain TeX
- termmenu: The package provides support for terminal-based menus using expl3
- plain-cm: Variable sized fonts in Plain TeX