Ultima Online

Gamingtreasures
sales of Ultima online gold, houses, accounts, tokens, gametime
http://www.gamingtreasures.com

Leading Entertainment Online
Sale of gold, artifacts, powerscrolls tokens gametime and codes, offers brokering services. All shards covered.
http://www.leogaming.com

Onlinegametrader.net
Skill guides, rares information, vendor shop listings, and information on bads.
http://www.onlinegametrader.net

RPG-BAY
A website dealing in the RMT virtual trade of Ultima Online gold and items
http://www.rpg-bay.com

SearchUO
A database of items on all servers. Players can search and find exact locations and prices to purchase from.
http://www.searchuo.com

Tradespot.net
Community news, game updates, shard information, and active player forum boards for in-game trading of rares, houses and other items and services.
http://www.tradespot.net/

UO Brokers
Contains trade forums, including X-Shard brokers and item/gold sales.
http://uobrokers.com

UO Rares
Third-party broker offering to facilitate the trading of rares in-game for real-life cash.
http://www.uorares.com/

UOForums
Growing community with trading boards for all shards, and private guild forums available on request.
http://uoforums.com/