Latex is a typesetting system that is widely used in documents with a lot of mathematical and technical content, but it is equally suited to the humanities. Here are a few packages relevant to fine typesetting of humanistic texts.
latex2doc
The biggest problem for an academic outside of the hard sciences using Latex is when you have to submit your work in MS Word format, as is usually the case for journals in the humanities. The problem is that simple, naive converters will not translate your complex bibliographical referencing. Latex2doc is a strategy to solve this problem.
ellipsis.sty
ellipsis.sty is a package that corrects the spacing around ellipses in LaTeX.
Polytonic Greek
Before Unicode, it used to be that the best solution for polytonic Greek with TeX was to use Pierre MacKay's Ibycus font. To that end, I wrote some LaTeX support for it. But nowadays you should use Jonathan Kew's XeTeX for Unicode-based TeX, along with an OpenType font, such as one the excellent free fonts from the Greek Font Society or one of Adobe's commercial offerings.
I have written a script called elhyph-utf8 that takes the hyphenation patterns from the elhyphen package by Dimitrios Filippou and modifies them to work with XeTeX. There are similar offerings available on CTAN.
quail-conv.el
I wrote an Emacs package called quail-conv to translate legacy polytonic Greek text from the Ibycus input encoding to utf-8. I would also work for other encodings (also non-Greek) which are too obscure to be covered by the standard run of encoding conversion software.