Red October BBS files - Red October was the semi-official Hero BBS for many years. The Mactyres now host this archive of Articles, Campaign Backgrounds, Characters, Rules, and Supplemental Material. The real treasures are in the File area, but only in Zipped text, unfortunately.
Hero System FTP Archives - The Hero System archive at ftp.cs.pdx.edu used to be the main Internet Hero repository before the Web, rivalling Red October. Still have many Champions characters, FH beasties and spell colleges, house rules, spreadsheets, and other files. Most GZip format.
HERO System Movement and Throwing - Tries to more consistently follow the laws of physics, without becoming overly complex.
Game Master's Superpowered Web Site - Home of: the Gamemaster's SuperPowered Companion - a DOS based program to run Hero System combat; QuickRoll Die Table Generator - will print random charts of 5d6 to 20d6 rolls that are cross indexed to a single % roll; alternative PostScript character sheets.
The Stuff Heroes Are Made Of - Home of the Champions Mailing List (4 week archive). "Justice League of Alabama" campaign site: writeups and annals. Comprehensive Hero and Superhero Amazon on-line book store. 20 package deals, 2 Fantasy Hero magic systems, 50 items, jousting. 13 comic book writeups. Cardboard Heroes jpegs. MSH SAGA to Hero conversion.
EZ Hero - Online bimonthly magazine for the HERO System, covering multiple genres with characters, plots, props, and gaming advice. PDF format archives and excerpts from current issue.
Brian's Hero Games Pages - Details of characters, campaign backgrounds, and other information for Fantasy, Pulp, Traveller, and Western Hero, with emphasis on a Fantasy Hero campaign set in 16th century Japan.
Hero Links - Sengoku Campaign - 16th century Japan, with character sheets, maps, adventure threads, background information and fiction. Gothick Empires campaign - Fantasy Hero, magic and technology in a renaissance-era setting. Characters and character art from other games. Random Fantasy Hero character generator for NPCs for Gothick Empires. House rules (mostly for Heroic-level games) also adopted by other groups.
The Official Haymaker! Homepage - Haymaker! is an amateur press association magazine (APAzine, or fanzine) about Champions and the rest of the Hero System founded in 1992. It is a collaborative effort of many of Hero System's best authors, and is a proving ground for many story ideas, characters, mechanics, general rules, or whatever the contributors want to write about.
The Wild Hunt - Ghost Archer and the Wild Hunt: superhero campaign in the San Francisco Bay area. Tribute to the Uncanny X-Men. Hundreds of character write ups, picture galleries. Tark's Fantasy Hero pages including large general store of item costs and weights. Hero System rules page.
Hero Games Company - Official home of Hero Games, publisher of the Hero System, Champions, and co-publisher of Fuzion/Champions: The New Millennium.
Gary Kleppe's Champions Page - House rules for Present-day Superheroes; Star Force (Future Agents); Galactic Guardians (Future Superheroes); and Future Rebels. Ranma Hero: a Champions campaign based on the Ranma 1/2 Manga, including 14 writeups.
HERO System Stuff - Information on several campaigns (Fantasy, Space Opera, Pulp) as well as some useful charts and graphics for tabletop miniatures.
Circle of Heros - A web ring linking sites that are of particular interest to Hero System players.
Unofficial Champions Home Page - The first Champions Web page, Theala Sildorian's page is still worth looking at for the Hero Gossip column and Chris Avelone's Stick Figure Theater among others. It is rarely updated, though.