Most of these PDF files are available from http://www.ctan.org/, possibly in Postscipt or DVI format.

A very helpful guide for producin PDF files (including ones will nice clickable references is available here

- LaTeX General/
- General guides to LaTeX, including
introductory guides.
- Not so short LaTeX Guide
- The excellent "Not so short LaTeX Guide"
- LaTeX User Guide for Authors
- Guide from the LaTeX Distribution
- pdfTeX User Guide
- Guide from the pdfTeX Distribution
- LaTeX Primer
- The Indian TeX Users Group LaTeX Primer

- AMS LaTeX/
- American Math Society (AMS) LaTeX Extensions.
- AMS LaTeX Manual
- Manual of the American Math Society LaTeX Extensions - recommended for maths typesetting
- AMS Theorem Package
- provides theorem, remark etc environments.

- Quick ref cards/
- TeX, LaTeX and emacs quick
reference cards
- Maths symbols
- Contains most of the symbols LaTeX can produce.
- AMS LaTeX ref card
- Comprehensive LaTeX reference card geared towards AMS maths
- AMS TeX ref card
- An AMS TeX (not LaTeX) reference card
- emacs ref card
- Includes the keyboard short-cuts - good if stuck in text mode!

- packages/
- Useful packages manuals
- authorindex
- Produces an author index.
- booktabs
- Produces "publication quality" tables in LaTeX
- beamer
- Produces good quality slides in LaTeX (competitor to Prosper)
- calc
- Allows arithmetic to be performed in LaTeX
- captcont
- Allows the retaintion of figure or caption numbers across different float environments.
- geometry
- Makes changing margins, headers, footers etc much easier.
- graphicx
- Package for including graphics.
- hyperref
- Allows you to created PDF files with hyperlinks.
- ifthen
- Provides "if", "then" etc facilites for LaTeX.
- keyval
- Provides a the ability to write commands with named parameters (used in creation of packages).
- mathclap
- Not actually a package, but explains how to stop LaTeX allocating horizontal space (like a horizontal \smash).
- pdfscreen
- pdfscreen
- prosper
- Creates slides for using LaTeX.
- Making Powerpoint-like Presentation with LaTeX.
- prosper example
- prosper introduction
- prosper tour
- psfrag
- Replaces Postscript text within a postscript file - good for labelling figures.
- rotating
- Provides rotating features. It is better to use graphicx to perform this functionality if possible.
- somedefs
- A toolkit for package programmers.
- subfigure
- Allows nice presentation of subfigures.
- supertabular
- Allows advanced tables (eg split over a page).
- tabularx
- Allows automatically sized column widths in tables.
- verbatim
- Allows text to be entered verbatim.
- xspace
- .

- bibtex/
- BiBTeX - referencing index system.
- bibtex manual
- Users guide to BibTeX.
- bibtex style design
- Guide to creating/edit BibTeX styles.
- harvard bibtex style
- Guide to the Harvard family of BiBTeX styles.
- natbib
- Natural sciences citation styles.

- misc/
- Other useful manuals
- epslatex
- General information on the inclusions of graphics in LaTeX - very useful.
- symbol list
- A comprehensive list of all sybmols LaTeX can produce.