The following are auction houses that predominantly (and most exclusively) deal is sports 
related collectables and memorabilia.

Heritage
Grey Flannel
Steve Novella
Huggins & Scott 
RMY Auctions 
SportsCardLink 
RR 
Baggers 
Sirius Sports 
Goodwin & Company
Love of the Game
PWCC 
JVSC 
Paragon
REA 

Brockelman & Luckey
Goldin 
Pristine 
Legendary 
Sterling 
MEARS 
Small Traditions
Treasure Tidbits
Collect 
SCP 
Lelands
Iconic 
Memory Lane
Lew Lipset
Champs & Bums