What are some alternatives?
Agile Domain Search - Search great domain names for your website in seconds.
Startup name check - Startup Name Check is a free service allowing you to validate names for your next startup, side hustle or side-project. Works for numerous domains and social networks. All information is displayed in a clean table layout.
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
Nomino - Find a cool name for your product
Undeveloped - Domains you never thought were available
Get.blog by WordPress - Prebook .blog domains before it's open to public