DomainMOD - DomainMOD is an open source application written in PHP & MySQL used to manage your domains and other internet assets.
WhoisThisDomain - Domain name lookup tool that allows you to get information about domain registration from WHOIS server.
Domain-Monitor.io - Looking for the complete domain and website uptime monitoring solution? Domain Monitor keeps an eye on your website, cron, SSL and domain name 24/7 and will alert you through Email, SMS and web when something stops working.
Whoisology - Connected database of whois records and whois history
Tough Domains - Tough Domains is platform that provides tools to manage internet domains, domain insights, and domain monetization.
Bulk Whois API - Bulk Whois API is a provider of parsed WHOIS data in JSON with simple API, competitive pricing, top notch support, and more.