On this page you will find a variety of useful links for writers to websites and resources which specialise in providing help and advice.
This link includes a selection of resources designed to help you improve your English grammar.
Follow this link for a collection of Netflix videos which can help with English language learning. These are aimed more at people learning English as a second language but it is worth scrolling through the page to see if there is anything useful.
This link includes a list of over 300 writing courses in a variety of genres and niches. However, you can just do a search for a specific genre (for example, nonfiction) and by price range (from free to $500+).
This link has been recommended to me by the creator because it is both a resource for enthusiastic Scrabble players (it unscrambles random letters into words) and it also includes an English grammar section which includes useful information about the different parts of speech.