Quizzes, tests, exercises and puzzles to help you learn English as a Second Language (ESL)
This project of The Internet TESL Journal (iteslj.org) has thousands of contributions by many teachers.

"Grammar is the collection of rules and conventions that make languages go. This section is about Standard American English, but there's something here for everyone."

"...offers quizzes, games and tutorials on all devices for people learning English as a Second Language at different levels. The Blues in the title refers to problems students have when learning. The site focuses on common errors students make, and it offers quizzes and explanations that allow them to correct these errors and check their progress."

Includes grammar and mechanics, plagiarism and academic honesty, practice and exercise, and workplace writing.

"The perfect composition textbook for college ESL students. This book was designed by students for students! Its easy to understand vocabulary, informal tone, and concise nature will ensure students actually read the book and learn from the content."
This is a Free, Online Open Educational Resource

Contains three levels of interactive grammar lessons and reading activities for beginning students of ESOL (English for Speakers of Other Languages). The grammar section includes a select set of YouTube videos, and the three original readers include short picture or chapter stories. Each lesson is accompanied by self-correcting exercises.
This is a Free, Online Open Educational Resource

"Addresses some of the most frequently occurring verb errors made by English as a Second Language (ESL) students."

"Every aspect of English language is described in detail and clearly explained with relevant examples."

"Learning grammatical terms is essential to take your language study or writing skills to the next level. If you're learning a foreign language in a classroom setting, then you must know the grammatical terms so you and your tutor can discuss language structures efficiently. If you're looking to improve your writing, then you must know the grammatical terms to remove the guesswork from aspects such as punctuation, sentence structure, and capitalization."

" ESL learners from the secondary school level to tertiary level as well as learners who are preparing to be English teachers will find the aspects and depth of the contents covered in this book useful. "

"Using punctuation correctly is essential to add clarity and precision to writing. More specifically, punctuation controls how information is grouped, how it flows, and how it is emphasized. In other words, it controls how readers absorb the text presented. "

"targeted for upper intermediate English language learners who are still polishing their foreign language skills and want to practice translation in certain fields. By the end of the book, English language learners will have practiced translation, considered to be the fifth skill to be developed after the four basic ones: listening, reading, speaking and writing."