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
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
Standard Notes - A safe place for your notes, thoughts, and life's work
Nylas Mail - The Nylas Cloud API powers your application with email, calendar & contacts features. Built-in features for better email, calendar, and contact management.
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.