There are many wonderful books for Middle Grade readers out there. Here are some lists to help you find the right ones for your MG readers.
Publishers Weekly offers their list of the best middle grade books of 2016
https://best-books.publishersweekly.com/pw/best-books/2016/middle-grade
School Library Journal provides their best of list for 2016 at: http://slj.com/bestof2016/middlegrade.php
Book Riot has 100 Must-Read Middle Grade Books for the Summer https://bookriot.com/2017/06/05/100-must-read-middle-grade-books-for-the-summer/
And 100 must-read MG Fantasy books from the last 10 years: https://bookriot.com/2017/08/08/middle-grade-fantasy/
Kirkus Reviews gives you BEST MIDDLE-GRADE BOOKS OF 2016 BY CATEGORY: https://www.kirkusreviews.com/issue/best-of-2016/section/middle-grade/lists/
Colours of Us provides their list of The 15 Best Multicultural Middle Grade Novels of 2016: http://coloursofus.com/the-15-best-multicultural-middle-grade-novels-of-2016/
The New York Society Library has a list of MG books for girls: https://www.nysoclib.org/children/girls-read-middle-grade-books-girls
For the graphic novel fans, Goodreads has a list too, but just to note, it is both MG and Young Adult, and YA’s rules for content are vastly different than MG, so if that’s a concern for you, you may want to screen them. https://www.goodreads.com/list/show/23516.Best_Middle_Grade_YA_Graphic_Novels
The Guardian has a list, Top 10 children’s books on death and bereavement, and though it’s not all MG, it’s a topic that is often asked about. https://www.theguardian.com/childrens-books-site/2015/feb/05/top-10-childrens-books-on-death-bereavement-holly-webb
School Library Journal offers suggestions for bereavement too: http://www.teenlibrariantoolbox.com/2017/08/a-grief-moderated-middle-grade-fiction-for-young-readers-dealing-with-loss-guest-post-by-kerry-sutherland/
And to lighten the mood, Barnes and Noble has a list of humor books for MG: https://www.barnesandnoble.com/blog/bust-a-gut-books-for-middle-grade-readers/
C.K. Sullivan 