Expresso - The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer with an extensive knowledge of regular expressions.
Blurt - Compose efficiently. Edit smartly. Stay on track. Blurt is all you need to write — in one sleek tool.
Writefull - Writefull provides you with the tools you need to improve the quality and consistency of your writing.
Ulysses.app - A powerful writing tool for Mac, iPad, and iPhone
Grammarly - Clear, effective, mistake-free writing everywhere you type.
Rapidweaver - A WYSIWYG web editor for mac.