http://japanesetest4you.com/category/jlpt-n1/jlpt-n1-grammar-test/
https://www.jpdrills.com/quizzes/48/JLPT_N1_Grammar/Quiz
http://www.tanos.co.uk/jlpt/levelcheck/grammar/jlpt1/
http://web.ydu.edu.tw/~uchiyama/kentei/index.html