5 Minute English
This is a good site for ESL learners containing short, easy explanations and exercises.
20 Grammar Rules
Provides 20 simple rules and tips to avoid making mistakes in English and an exercise to ensure you understand those rules.
The Blue Book of Grammar and Punctuation
This site provides free English rules, real-world examples, free sample quizzes, and newsletters
The Chicago Manual of Style - Q&A
You can submit a question or browse the Q&A section of the CMOS to get useful information related to grammar and style.
Common Errors in the English Language
Professor Paul Brians of Washington State University has compiled a list of common errors in English. He gives lucid explanations for when to use common words such "a" and "an" and explains the difference between words commonly misused.
Explains the use of gendered language in writing
Includes detailed terms, many interactive exercises, useful handouts, PowerPoints, videos, and more
Contains free English Grammar lessons and interactive tests.The site links to easily confused words, grammar glossary, common mistakes and more.>
Guide to Grammar and Style - Jack Lynch
"It includes a number of specific rules, dozens of commonly misused words, and bundles of suggestions for improving your style."
Online Editor- Grammar Check
Enter text in the Grammar Check form to get instant corrections and suggestions. The site has infographics for common Latin terms, common words that confuse, how to check grammar in Gmail, Yahoo, and Outlook, etc.
Purdue Online Writing Lab: Grammar
This area includes resources on grammar topics, such as count and noncount nouns, articles (a versus an), subject-verb agreement, and prepositions.
Refdesk.com - Grammar, Usage, and Style
A practical, authoritative guide to contemporary English usage. "The site presents sound guidelines and specific controversies in grammar, style, and word choice."
Strunk's Elements of Style
Free kindle book and ePub digitized by Project Gutenberg.
Ted-Talks- Be a Better Writer in 15 Minutes
Contains four Ted-Ed lessons on grammar and word choice.
The Use of "And"
When and how to use the conjunction "and".
Voice of the Shuttle: Style and Grammar Guide
A guide to grammar and writing including bibliographic style guides and manuscript preparation guides for online resources.