Suggestions for soul

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

Package soulpos: A fancy means of underlining
Package dashundergaps: Produce gaps that are underlined, dotted or dashed
Package lua-ul: Underlining for LuaLaTeX
Package ulem: Package for underlining
Package spacekern: Kerning between words and against space
Package letterspacing: Letter spacing
Package wiggly: Draw wiggly lines under text
Package underlin-generic: Multi-word underlining
Package expex: Linguistic examples and glosses, with reference capabilities
Package dirtree: Display trees in the style of windows explorer
Package musixtex: Sophisticated music typesetting
Package ligtype: Comprehensive ligature suppression functionalities
Package microtype: Subliminal refinements towards typographical perfection
Package noitcrul: Improved underlines in mathematics
Package xypic: Flexible diagramming macros
Package autoaligne: Align terms and members in math expressions
Package epsf: Simple macros for EPS inclusion
Package hlist: Horizontal and columned lists
Package systeme: Format systems of equations
Package xlop: Calculates and displays arithmetic operations
Package chemfig: Draw molecules with easy syntax
Package fixjfm: Fix JFM (for *pTeX)
Package polexpr: A parser for polynomial expressions
Package witharrows: Aligned math environments with arrows for comments
Package nccstretch: Insert a stretch between each token of a string
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