Postbox is a popular alternative to the macOS Mail app, with versions for both Mac and Windows. It supports features that are designed to help tame active inboxes, with a focus on speed and customizability. Content received by email can be shuffled off to popular cloud services, including Dropbox, Box and One Drive and pre-defined responses help you churn through email with ease and efficiency.
The Mac version’s feature set includes OmniFocus integration. Specifically, you can tap into the “OmniFocus: Send to Inbox” feature by control or right-clicking on a message. If no text is selected the Quick Entry dialog will pop up with the action’s title matching the subject of the email and a link to the email in the notes field. If this feature is triggered with text selected, the selected text is automatically added to the notes field of the new action, along with the link to the email.