Core Grammar for LawyersSM (CGL) is an online, self-directed learning tool designed to help law students and practicing attorneys acquire the grammar and punctuation skills that are prerequisites to successful legal writing. Small fee to use.
Alphabetically arranged list of words and their uses, interspersed with longer entries about larger questions of uses and style (eg. abbreviation, capitalization, etc.)
General Grammar Resources
Grammar Check on Microsoft Word
1. To fix settings, go to File>Options>Proofing>Writing Style>Settings
2. Open a document, then click on Review>Spelling and Grammar.
Checks for spelling, punctuation and grammar for free. You must buy a subscription in order to check for advanced issues, such as word choice, passive voice, weak or uncertain language, wordiness, unclear referent and more.
A desktop app for Mac and PC, not a mobile app. "Hemingway helps you write with power and clarity by highlighting adverbs, passive voice, and dull, complicated words." $19.99.
The Online Writing Lab (OWL) at Purdue University houses writing resources and instructional material, and we provide these as a free service of the Writing Lab at Purdue. Students, members of the community, and users worldwide will find information to assist with many writing projects.
The Redbook by 
Modern English Usage, 4th ed. by 
