Finding reputable sellers on a Bitcoin Ordinals Marketplace requires some due diligence. Start by checking the seller's ratings and reviews. Look for sellers with positive feedback and a history of successful transactions. It's also helpful to review any additional information provided by the platform, such as seller verification or identification processes. If possible, communicate with the seller directly to ask questions or clarify any doubts. Trust your instincts and be cautious of deals that seem too good to be true.