A brief description of the packages here:

The "larger" packages by the LaTeX team:
  amslatex	to use the Ams-fonts, many useful math stuff ...
  babel		support for multiple languages
  base		the base LaTeX system
  graphics	some graphics: color, rotation, PostScript
  mfnfss	support for more mf-based fonts
  psnfss	support for more PostScript fonts
  tools		tools for various things, well documentated in
		texmf/doc/latex/tools

Other "larger" packages:
  script	alternative classes, more "european" than the standard ones
  seminar	producing slides

More support for non-english LaTeX users:
  ntgclass	macros from the "Nederlandstalige TeX Gebruikersgroep"
  dinbrief	german letters
  g-brief	german letters (Geschaeftsbriefe)

Lots of one-file packages:
  misc

Local configuration:
  local

Smaller packages for special things:
  eepic			more enhancements to the picture environment
  fancyheadings		customizing page styles
  labels		making labels
  mflogo		using the LaTeX logo font
  minitoc		creates mini-table of contents
  supertabular		extensions to the tabular environment
  textmerg		merging textes
  wasysym		using the wasy font with LaTeX
