Suggestions for smart-eqn

The following packages have something in common with the package smart-eqn. The packages are ordered in decreasing similarity.

semantex: Semantic, keyval-based mathematics
cascade: Constructions with braces to present mathematical demonstrations
ebproof: Formal proofs in the style of sequent calculus
flexisym: Symbol manipulation for breqn
semtex: Deals with stripped SemanTeX documents
numerica: Numerically evaluate mathematical expressions in LaTeX form
longdivision: Typesets long division
diffcoeff: Write differential coefficients easily and consistently
derivative: Nice and easy derivatives
rec-thy: Commands to typeset recursion theory papers
create-theorem: Initializing and configuring theorem-like environments, with multilingual support
pascaltriangle: Draw beautiful Pascal (Yanghui) triangles
simples-matrices: Define matrices by given list of values
letterswitharrows: Draw arrows over math letters
mathcommand: \newcommand-like commands for defining math macros
rbt-mathnotes: Rebecca Turner’s personal macros and styles for typesetting mathematics notes
numerica-plus: Iteration and recurrence relations: finding fixed points, zeros and extrema of functions
iwonamath: LaTeX support for scaled Iwona math fonts
numerica-tables: Create multi-column tables of mathematical functions
schulmathematik: Commands and document classes for German-speaking teachers of mathematics and physics
unicode-math-input: Allow entering Unicode symbols in math formulas
leftindex: Left indices with better spacing
proflycee: A LaTeX package for French maths teachers in high school
nicematrix: Improve the typesetting of mathematical matrices with PGF
lualatex-math: Fixes for mathematics-related LuaLaTeX issues
upgreek: Upright Greek letters
endiagram: Easy creation of potential energy curve diagrams
substances: A database of chemicals
enotez: Support for end-notes
chemformula: Command for typesetting chemical formulas and reactions
erw-l3: Utilities based on LaTeX3