abbrev – macros for defining abbreviations in documents
abstract – typeset abstracts of documents
accessible – accessibility support
acrobat – relies on availability of Adobe Acrobat, etc.
acronym – define and use acronyms
addr-list – lists of addresses, for a personal directory (or the like)
advert – small advertisements, fly sheets, etc.
albanian – support for typesetting Albanian
alignment – tables, tab structures, etc
alignment-supp – ancillary code for tables, tab structures, etc
amharic – support for typesetting Amharic
apa – typesetting according to the rules of the American Psychological Association
appendix – Typsetting and using appendices
arabic – documentation in and support for typesetting Arabic
arch-tree – Root directory of a (sub-)tree of the archive
archival – creating archival copies, or copies for distribution
arithmetic – perform and typeset arithmetic problems
armenian – support for typesetting Armenian
article-like – LaTeX article classes and their developments
astrology – fonts and typesetting for astrologers
astronomy – astronomy articles, astronomical charts
automata – finite-state machines, automata, labelled graphs, etc.