Most domain conferences host an auction that consists mainly of premium domains, also internet platforms have started auctioning off domains. Although one could assume that auctions are a good place to sell domains that is not always true. As most participants are also domainers chances are you will not get a price close to what an enduser would pay. Of course there are sometimes major exceptions when a bidding war starts. Ebay also has a domain section but it is not recommended to list your names there, as domains are often overlooked so you will hardly get the price you are expecting.