Here are some of my most used trading card website for buying, trading cards or reference :
Beckett Media : http://www.beckett.com/
Canadian Hockey Cards : http://www.canadianhockeycards.com/
Canadian Sport Card Traders group : http://www.freewebs.com/csctraders/
Center Ice Collectibles : http://www.centericecollectibles.com/index.aspx
Check Out my Cards : http://www.comc.com/
Ebay : www.ebay.ca
Kronozio : https://www.kronozio.com/?l=fr
L'Imaginaire : http://www.imaginaire.com/indexv2.jsp?url=/lib/jsp/sectionv2.jsp&cat1=CA&langue=fr
ParallelDave's Hockey cards : http://www.paralleldave.ca/
Sports Card Forum : https://www.sportscardforum.com/forum.php
Sportlots : http://www.sportlots.com/
Ultimate Hockey Checklist : http://www.ultimatehockeychecklist.com/
Upper Deck : www.upperdeck.com