Domcomp - No-nonsense domain price comparisons, updated daily
Brandpa - Domain names for startups
Pricepeek - Compare prices of the same product across all Amazon locales
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
dofo.com - Domain search platform Dofo.com gathers all registered (350 million) domains of the world in a single place. Dofo also brings together all the domain names that are on sale, provides useful features, all completely free.
Domainr - Domainr is the only ICANN-accredited domain status API provider.