Suggestions for complexity
The following packages have something in common with the package complexity. The packages are ordered in decreasing similarity.
- computational-complexity: Class for the journal Computational Complexity
 - harpoon: Extra harpoons, using the graphics package
 - actuarialsymbol: Actuarial symbols of life contingencies and financial mathematics
 - actuarialangle: Angle symbol denoting a duration in actuarial and financial notation
 - circledtext: Create circled text
 - bootstrapicons: Icons from the framework Bootstrap
 - rorlink: Create ROR symbols which links to the given ROR-IDs
 - oplotsymbl: Some symbols which are not easily available
 - orcidlink: Insert hyperlinked ORCiD logo
 - isosigns: ISO signs and colors according to the standards 7001, 7010 and 3864
 - cmarrows: METAPOST arrows and braces in the Computer Modern style
 - tikzpfeile: Draw arrows using PGF/TikZ
 - harveyballs: Create Harvey Balls using TikZ
 - sacsymb: “Sacred Symbols” prepared with TikZ
 - tikzsymbols: Some symbols created using TikZ
 - pdfmsym: PDF Math Symbols — various drawn mathematical symbols
 - open-everyday-symbols: A list of “everyday” symbols, to be extended by everybody
 - pgfornament-han: pgfornament library for Chinese traditional motifs and patterns
 - kksymbols: LaTeX commands for enclosing characters in circles, squares, diamonds, or brackets
 - tiscreen: Mimic the screen of older Texas Instruments calculators
 - emo: Emoji for all (LaTeX engines)
 - pict2e: New implementation of picture commands
 - graphbox: Extend graphicx to improve placement of graphics
 - graphics-cfg: Sample configuration files for LaTeX color and graphics
 - pdftex-def: Colour and Graphics support for pdfTeX
 - dvipdfmx-def: Configuration file for dvipdfmx graphics
 - graphics-def: Colour and graphics option files
 - curve2e: Extensions for package pict2e
 - figsize: Auto-size graphics
 - bez123: Support for Bezier curves
 - curves: Curves for LaTeX picture environment