- Adam Warshaw's Boxing Page
- "America's National Game: The Albert G. Spalding Collection of Early Baseball Photographs"
- Autograph Alert
- Autograph Magazine
- The Autograph Network
- Baseball Cards, 1887-1914
- Baseball Games: Antique Parlor Games
- Baseball Glove Collector
- Baseball & Tobacco
- Baseball Wrappers
- Beckettpedia
- Blacksox Fan
- Card Shop Finder.com
- Cycleback's Baseball Museum
- Cycleback's Print & Photographs
- Caramel Cards
- The Conlon Collection
- Cuban Ball
- Cuban Baseball Cards
- English Football Cards
- Game Used Universe
- Leon's Type Card Collection
- Library of Congress: Spalding Baseball Guides 1889-1939
- Old Cardboard
- Open Checklist
- Postcardy.com (postcard collecting)
- Real Photo Postcard Stamp Boxes
- Sports Action Figures
- Sports Antiques
- TeamSet4U
- Ticket Stub Collection
- Topps Production Codes
- Vintage Ball
- Vintage Football Card Gallery
- Virtual Card Collection
Collectibles Companies:
- AFA-Toy Graders
- Beckett Grading
- Beckett Price Guides
- CGC-Comic Book Graders
- Collectors Universe- PSA
- Donruss- Panini America
- Hartland of Ohio
- In The Game Trading Cards
- JSA- James Spence Authentication
- Leaf Trading Cards
- Panini America
- Panini America Blog
- SGC
- Spawn.com- McFarlane Figurines
- Sports Collectors Digest
- Sports Speakers
- Topps
- Tuff Stuff
- Upper Deck
- 19th Century Only
- American Memorabilia
- Brockelman & Luckey
- Classic Auctions
- Clean Sweep Auctions
- Collect.com Auctions
- Cuban Baseball Auctions
- eBay
- Gaynor & Dent
- Goodwin & Co.
- Grey Flannel Auctions
- GSA Auctions
- Hakes Auctions
- Heritage Auction Gallery
- Huggins & Scott
- Hunt Auctions
- Imperial Sports Auctions
- Legendary Auctions
- Lelands
- MEARS
- Memory Lane, Inc.
- Mile High Card Company
- Old Judge
- Robert Edwards Auctions- REA
- SCP Auctions
- Sportslot
- Blowout Cards Forum
- Full Count Vintage Baseball Card Forum
- Netshrine
- Sports Card Forum
- Sports Collectors Social Network
- Vintage Baseball Card Forum: Net54
- Vintage Hockey Card Forum
- Vintage Non-Sports Card Forum
- Agate Type
- Back to Baseball
- Baseball Almanac
- Baseball America
- Baseball by Positions
- The Baseball Cube
- Baseball in Wartime
- Baseball Library
- Baseball Prospectus
- Baseball Recordings
- Baseball Reference
- Baseball Reliquary
- Baseball Think Factory
- Baseball Writers Association of America (BBWAA)
- Black Baseball
- Business of Baseball Pages
- Center for Negro League Baseball Research
- Cot's Baseball Contracts
- The Deadball Era
- Dressed to the Nines
- FanGraphs
- The Girls of Summer
- Japanese Baseball
- Library of Congress: Historical Baseball Resources
- Minor League Central
- National Sports Collectors Convention
- Negro League Baseball Players Association
- Negro League Legends
- Retrosheet
- Rotoworld
- SABR: The Baseball Biography Project
- SABR: Society for Advancement of Baseball Research
- Seamheads.com- Negro League Stats
- Sports Club Stats (Playoff Chances)
- Sports Logos
- USA Baseball
- Wikimedia Commons
- Babe Ruth Museum
- Bob Feller Museum
- Chicago Baseball Museum
- Emmett Kelly Museum (famous Dodgers "Bum" clown)
- Little League Baseball Museum
- Louisville Slugger Museum & Factory
- National Baseball Hall of Fame
- Negro League Baseball Museum
- Newport Sports Museum (Orange County, California)
- Shoeless Joe Jackson Museum
- Sports Museum of Los Angeles
- Ted Williams Museum and Hitters Hall of Fame
- Ty Cobb Museum
- Yogi Berra Museum & Learning Center
