A screenshot of Mailbox for iPhone.
You're probably all-too-familiar with the concept of snoozing your alarm clock. But what about snoozing your email? Mailbox recognises that you can't always action your messages immediately, and it offers a handy snooze function that lets you put off processing them until later today, tomorrow, this weekend or another date. Once the snooze period is over, the message reappears in your inbox. Unfortunately, it only supports Gmail accounts.
Evomail is heavily inspired by the excellent Mailbox app, with a similar fresh interface and the ability to snooze emails for a later date. But it brings a few neat extras to the table. There's support for more email accounts, such as Yahoo!, Gmail, Exchange and iCloud, and you can add file attachments directly from the Dropbox and Box cloud storage services. An Android version is also in the works.
The best thing about Dispatch is that it doesn't operate in a vacuum. Built-in support for 18 different apps and services means you can do a lot more with your email, such as save links to Pocket, archive emails to Evernote and create a task in Reminders. Sadly, it's limited in other ways. You don't get push notifications for new email, there's no search function and you can't add attachments.
Out of the box, Android has an excellent app for Gmail and another, not-so-excellent app for every other email service. MailDroid lets you merge all of your accounts into a single inbox and throws in some powerful email handling features such as support for custom rules (similar the ones in Microsoft Outlook), a spam filter and the ability to add attachments from cloud storage services such as Google Drive and Dropbox.
Aqua Mail is another 'unified' email client for Android that supports all of the major email services and protocols. Those who receive attachments on a regular basis in particular will love Aqua Mail, as it includes a separate tab in each message for attachments and you can save them to your memory card or any other folder of your choosing.