ebook – support for preparing e-books
editor – editor designed (or adapted) for use with (La)TeX
editor-extn – plug-ins for editors, for better (La)TeX and Meta* support
editorial – editor’s marks, highlights, etc.
editorial-consistency – ensure consistency of usage
electronic – support of electronic design
emphasis – emphasising text
enc-juggle – conversion between encodings
endnote – notes typeset at end document
engine – TeX (or TeX-alike) typesetting engine
engineering – typesetting associated with engineering of whatever sort
english – typesetting specific to English
env-query – examine the TeX programming environment
epigram – short quotation typically associated with the start of a chapter
error-supp – control of LaTeX error messages
esperanto – support for typesetting Esperanto
essay – course work essays, assignments, etc.
estonian – support for typesetting Estonian
exam – exams, quizzes, etc.
exec-foreign – execute ‘other types’ of language
exercise – exercises, problems for solution, etc.
experimental – offer of a facility that may never make its way to production use
expl3 – package uses experimental LaTeX 3
ext-code – run an external program from within a document
ext-svc – link to a service not on CTAN