What are some alternatives?
When comparing Domainr and Instant Domain Search, you can also consider the following products
namegrep - Domain name search with regular expressions and curated sets
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
Agile Domain Search - Search great domain names for your website in seconds.
Nuage - Nuage provides domain naming services.
NameBounce - NameBounce is an intelligent domain name and business name generator. Discover hundreds of new business name ideas with available domains, all for free!
NameMesh - 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!