Not only is the free CloudMagic one of the most capable email clients for Android, but it’s also one of the most innovative. It’s compatible with Gmail, Yahoo, Exchange, and just about any IMAP email server, and it offers multiple mailboxes in a single, clean interface.
But perhaps its most attractive feature is its "contextual card" concept, which integrates with some of the most widely used business tools. For example, the Salesforce.com card shows your Salesforce info for contacts and add emails and leads, while the Zendesk card lets you create and update tickets directly from an email. There are also cards for Evernote, Trello, and Mailchimp.