Suggestions for unouter

The following packages have something in common with the package unouter. The packages are ordered in decreasing similarity.

Package redefine: Conditional macro, etc., definitions
Package declare: Local register name declarations
Package defstring: Define macros as verbatim macros
Package laps: Zero-width boxes for annotations, etc.
Package extradefs: A miscellany of support macros
Package ifis-macros: Check if a given input string is a number or dimension for TeX
Package bibplain: Simple macros for using BibTeX with Plain TeX
Package hackalloc: Make allocations local
Package plipsum: Lorem ipsum for Plain TeX developers
Package automagic: Automatic counter numbering in Plain TeX
Package miniltx: An abstract of LaTeX facilities for use with Plain TeX
Package makerobust209: Make an existing LaTeX command robust
Package noprot: Avoid the need for protection
Package nextpage: Generalisations of the page advance commands
Package getoptk: Define macros with sophisticated options
Package balancedquotes: Code balanced quotes according to document language
Package compare: Macro to compare two strings
Package patch: Modify already-loaded packages
Package letter-plain: Letter macros for Plain TeX
Package figplace: Floating figures in Plain TeX
Package lettermac: Simple macros for writing letters (Plain TeX)
Package label-pln: Print address labels in three columns
Package plain-cm: Variable sized fonts in Plain TeX
Package twoside: Two-side typesetting in Plain TeX
Package toc-zar: Plain TeX table of contents macros
Package twocolumns: Knuth’s two-column output macros
Package list: Verbatim listing of text files
Package pi: Calculate pi
Package settosize: Scale text to given width
Package labelmac3: Print Avery 5160 labels for laser printers
Package autotoc: Table of contents in Plain TeX