Transferslot - Easily buy and sell side-projects
Mashword - Find a name and register a domain for your business, baby, project, and more. Mashword is a powerful company and human name generator that determines the pronunciations of entered words and then creates unique combinations and variations.
Freemarket - Domain marketplace from Freelancer.com
Panabee - Best way to search domain names, esp for apps and startups
Negotiante - Sell Website for Free
Mono Name - Curated CSV list of available domains for your next project