BrandHunt V2 - Search/track domain & social media handles in real time.
Marquix Startup Domains - Startup domains for less than $10k with payment plans
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
Domainz.io - Premium domains, for not so premium prices
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!
Registered Domains Search - Finds all already registered domain names