Grammar

http://www.learn-english-today.com/lessons/lessons_list.html

(English grammar rules, verb tenses and forms, vocabulary usage,
with exercises and word games..)

http://www.learn-english-today.com/lessons/exercise-list.html

(Over 100 online and printable exercises to help you revise your English)

http://www.synonym.com/synonyms/ (Synonym.com is the web's best resource for English synonyms, antonyms, and definitions.)
antonyms
http://www.englishgrammarsecrets.com/index.htmlRemember that learning grammar is only one part of learning a language. So don't be obsessed by it! Learning examples that will help you when you speak or write is the best way to learn.
http://www.englishmedialab.com/grammar.html(All your English Grammar exercises in one place in the form of ESL Quizzes, tests-grammar exam resources. Interactive Grammar Practice - Quizzes & Games in Flash.)
http://www.agendaweb.org/grammar/tests_quizzes1.html (grammar exercises)

https://wordwall.net/resource/491475/ing-infinitive

https://www.english-practice.at/

Present Continuous
https://youtu.be/r13tkkJ7uhk