http://games.byond.com/hub/Kajika/DuelMonstersOnline



You can tag team dual, tag team tournaments or 1 on 1 duals and tournaments available, also all the cards are available from the start and you can earn outfits by dualing. Probably one of the most consistant yugioh online out there. Try it out its completely free, all you need is to install the byond software and log on the the server. Over 100 people playing all the time