Grammarly - Clear, effective, mistake-free writing everywhere you type.
PlagiarismSearch - PlagiarismSearch is online service that detects plagiarized content.
LanguageTool - Free proofreading tool for OpenOffice, LibreOffice, Firefox, and Chrome.
Turnitin - Turnitin is preferred by educational institutions around the world for preventing plagiarism. Instructors at all levels of education can request that students use the service to submit papers, and Turnitin checks those papers for plagiarism.
Ginger - Powerful and effortless desktop & mobile solutions for improving your writing and productivity. Ginger Software is your personalized editor - everywhere you go.
Unicheck - The plagiarism checker Unplag scans across the internet, repositories, open sources content and databases. It delivers real-time results and has no cached data.