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Swashbuckling Adventures has an interesting system, though I do not know if it was original to that book.
Among other things, it allows a player to have his/her character lose a limb rather than die from a failed Massive Damage save - important in a setting were Raise Dead/Resurrection are not available. I found it very handy in a Steampunk game, where prosthetic replacements were available, but resurrection was not.
I've photocopied the Critical Hits table in Paizo's Dragon Compendium Volume 1 (p.233), and glued it into the interior cover of my 3.5 DMG. Has served me pretty well.
the original "Critical Hits and Misses" tables from Dragon #39 (not 3E, it was originally for AD&D, but it works just fine). ... you can actually pick up the original magazine here (when it's available that is).