IXL (website) (www.ixl.com)
How to Survive Middle School English (book)
Everything you need to Ace English Language Arts in One Big Fat Notebook (book)
Scholastic Guide to Grammar (book)
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These are some books that aren't focused on grammar but might help you learn more words with help you learn more words:
The Tripods book series by John Christopher
Number the Stars by Lois Lowry
The Emigrants by Vilhelm Moberg
The Chronicles of Narnia by C. S. Lewis
Harry Potter by J. K. Rowling
Hope this helps! (By the way, that isn't a book).