Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
Domainz.io - Premium domains, for not so premium prices
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
DomainWatch - Domain Monitoring Made Easy
Hiver - Manage Customer Support, Sales and Projects right from your Gmail inbox. Collaborate with Shared Labels, Shared Contacts, email notes, email reminders and email templates
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.