Suggestions for xstring

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

Package xesearch: A string finder for XeTeX
Package coolstr: String manipulation in LaTeX
Package ifvtex: Detects use of VTeX and its facilities
Package ifluatex: Provides the \ifluatex switch
Package nth: Generate English ordinal numbers
Package ifpdf: Provides the \ifpdf conditional
Package ifetex: Provides \ifetex switch
Package ctablestack: Catcode table stable support
Package expex: Linguistic examples and glosses, with reference capabilities
Package ifxetex: Am I running under XeTeX?
Package luatexbase: Basic resource management for LuaTeX code
Package multido: A loop facility for Generic TeX
Package multiexpand: Variations on the primitive command \expandafter
Package poormanlog: Logarithms and powers with (almost) 9 digits
Package path: Typeset paths, making them breakable
Package simplekv: A simple key/value system for TeX and LaTeX
Package texdimens: Conversion of TeX dimensions to decimals
Package zeckendorf: Knuth Fibonacci multiplication, Zeckendorf and Bergman representations of big integers
Package dirtree: Display trees in the style of windows explorer
Package mathdots: Commands to produce dots in math that respect font size
Package musixtex: Sophisticated music typesetting
Package gobble: More gobble macros for PlainTeX and LaTeX
Package luatex85: pdfTeX aliases for LuaTeX
Package metastr: Store and compose strings
Package xypic: Flexible diagramming macros
Package autoaligne: Align terms and members in math expressions
Package bidi: Bidirectional typesetting in plain TeX and LaTeX, using XeTeX or LuaTeX
Package epsf: Simple macros for EPS inclusion
Package hologo: A collection of logos with bookmark support
Package hlist: Horizontal and columned lists
Package ifptex: Check if the engine is pTeX or one of its derivatives