Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
BrandBucket - The original marketplace for business names and creative domain names.
Brandpa - Domain names for startups
Zlipa - Startup names with available dotcoms and logos
SafeSocial - Make the Internet a better place
NameMing - Get smart domain name suggestions using synonyms, suffixes, prefixes, short url, new gtlds to find the perfect domain name. Generate ideas for social user names and check availability for free!