TheRightMargin - TheRightMargin is a smart writing tool.
GradeProof - Proofreading with Artificial Intelligence
Writefull - Writefull provides you with the tools you need to improve the quality and consistency of your writing.
Nurtz - Proofreading concierge in your Slack
Analyze My Writing - Analyze My Writing is an online text content and readability analyzer.
Proofree - Free proof-reading by humans.