If you're looking for more grammar, you can look at getting the Kanzen Master grammar books.
https://www.amazon.co.jp/dp/4883195651/
If you're looking for alternative to the Dictionary of Japanese Grammar series, I've heard these are good:
https://www.amazon.co.jp/gp/product/4874241549/ (Japanese version)
https://www.amazon.co.jp/Handbook-Japane...874246788/ (English version)
https://www.amazon.co.jp/dp/4883195651/
If you're looking for alternative to the Dictionary of Japanese Grammar series, I've heard these are good:
https://www.amazon.co.jp/gp/product/4874241549/ (Japanese version)
https://www.amazon.co.jp/Handbook-Japane...874246788/ (English version)