NHL Uniforms - Pictorial overview of every NHL jersey
WHA Uniforms - Pictorial overview of every WHA jersey
NFL Uniforms Past and Present - History of NFL uniforms till 2003.
FootyJumpers.com - Aussie Rules (AFL) jumper history.
Colours-of-Football - Kits for football/soccer leagues worldwide.
Dressed to the Nines - Baseball Hall of Fame uniform database.
UniWatch - "The Obsessive Study of Athletic Aesthetics"
Game Used Universe - Complete site and auctions for collectors
The Spirit of the Game - Game worn NHL jersey auctions
Drop the Pucks - Hockey history through game worn jerseys.
Mei Gray - "Your source for game worn jerseys"
Mitchell and Ness - Authentic jersey reproductions
SSUR - The Society for Sports Uniform Research
Chidlovski.com - Russian hockey retrospective
Internet Hockey Database - Hockey player stats and team database
Hockey-Reference.com - Hockey player stats and team database
Pro-Football-Reference.com - Football player stats and team database
Basketball-Reference.com - Basketball player stats and team database
Baseball-Reference.com - Baseball player stats and team database
Baseball Almanac - Baseball rosters, results, stats and more
SportsLogos.net - Team logos and more.
Eriq Jaffe's Sports Fonts - Amazing stuff...