Microsoft Visual Studio - Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft.
MacDown - MacDown is an open source Markdown editor for OS X, released under the MIT License.
Visual Studio Code - Build and debug modern web and cloud applications, by Microsoft
iA Writer - Minimal Design, Maximum Focus
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.
MWeb - Pro Markdown writing, note taking and static blog generator