I'd like to say one small thing before going into details: Please contribute! Much effort has been put into this place, in the hope that it will be useful to as many people as possible. But we can't do it all by ourselves -- we need your help. If you have written a macro (or two?) of which you think that it might be useful, please contribute it to the archive.

Curiously enough, many people seem to be scared away by the idea that "their macro is not good enough to be published". Try to look at it this way: Nobody is perfect, nobody knows everything and nobody will be flamed if there is a minor stylistic deficiency in the code of a macro published here. Hey, do you know any better way to get your code debugged for free by several hundred volunteers? :-)

Enough for now, just have a look at the autoconf macros - they are grouped by category on the left side.

Downloading all macros at once

In case you want to download all macros at once rather than having to click through the whole list and access them individually, just get tarballs and rpm archives from the project's sourceforge filelist, where updates are posted every time a member of the archive changes or new macros are added.
 

further reading...

• GNU Autoconf configure maker
• GNU Automake makefile generator
• GNU Libtool sharedlibrary tool
• GNU M4 the macro processor
• RedHat Autotools project sources
• Autoconf Macro Archive at Cryp.To (Peter Simon)
• and AC Macro Archive at SF.Net (Guido Draheim)
  ............ including RPMs and tarballs
• Autogen to easily create new autoconf tests.