Instant Username Search - Check out if your username is available
Owler - Owler is a crowdsourced data model allowing users to follow, track, and research companies.
Namechk - See if your username is available on 100+ social networks
Whatagraph - Whatagraph is the most visual multi-source marketing reporting platform. Built in collaboration with digital marketing agencies
Handlescout - Get notified when a Twitter username becomes available
QlikSense - A business discovery platform that delivers self-service business intelligence capabilities