Spike is one of the most unusual, although highly useful in today’s fast-paced world, email clients. You can also supplement the features of this app by using plugins like Mail Act-On, however, they can only be used when your Mac is connected to the internet. Some of the newer features of this email client include the ability to email bigger-than-average attachments by using iCloud, access to VIP support and others. This is the perfect app for Apple enthusiasts who prefer tradition over innovation and choose to use programs that have proved themselves over the years, Apple Mail allows you to connect your Gmail, iCloud, Yahoo and other mailboxes into one universal inbox. Apple Mail is the classic email client for Mac and while it may seem like an unexciting choice for your main email app, it does everything it is supposed to and it works well for both advanced and novice users.