Force of Will:
http://fowtcg.us/
http://db.fowtcg.us/

MTG:
http://magic.wizards.com/en
http://mythicspoiler.com

Pokemon TCG
http://www.pokemon.com/us/pokemon-tcg
http://www.pokebeach.com/

Yu-Gi-Oh
http://www.yugioh-card.com/en/limited/
https://ygorganization.com

Roleplaying
http://dnd.wizards.com/
http://www.dmsguild.com/