You mean, in terms of developing on? Then I guess you're excluding the OnePlus One for Android development. And the iPhone 6/6+ for jailbreak and chrooting. And perhaps the BB Z30 for developing, well, alot of things (although released late '13, wasn't really available until '14).
I guess you're just gonna have to wait for the Jolla Tablet to release in 2015. Are you a backer?