Suggestions for threeparttable
The following packages have something in common with the package threeparttable. The packages are ordered in decreasing similarity.
- threeparttablex: Notes in longtables
 - mdwtools: Miscellaneous tools by Mark Wooding
 - notes: Mark sections of a document
 - debate: Debates between reviewers
 - mindflow: Write your ideas in a clear way
 - marginnote: Notes in the margin, even where \marginpar fails
 - versonotes: Display brief notes on verso pages
 - parnotes: Notes after every paragraph (or elsewhere)
 - cals: Multipage tables with wide range of features
 - ltablex: Table package extensions
 - xtab: Break tables across pages
 - nox: Adaptable tables
 - booktabs: Publication quality tables in LaTeX
 - tabu: Flexible LaTeX tabulars
 - supertabular: A multi-page tables package
 - xltabular: Longtable support with possible X-column specifier
 - stabular: Multipage tabular
 - todo: Make a to-do list for a document
 - easyreview: Package to provide a way to review (or perform editorial process) in LaTeX
 - easy-todo: To-do notes in a document
 - edmargin: Multiple series of endnotes for critical editions
 - fixmetodonotes: Add notes on document development
 - minipage-marginpar: Minipages with marginal notes
 - mbenotes: Notes in tables or images
 - fixme: Collaborative annotation tool for LaTeX
 - pagenote: Notes at end of document
 - zennote: Streamline your note-taking process!
 - unifront: Give notes a unique front page for every chapter and section
 - scrambledenvs: Create and print scrambled environments
 - snaptodo: A todo that snaps to the closer side
 - ezedits: Commands for tracking document changes and notes