That depends on your lessons. A business student needs very different books from a pre med student. Talk to teachers. Read reviews of your textbooks. What other books has the author written? What extra reading does your professor recommend?
I will make a few useful suggestions for any student.
1. Books on alternative uses for household items. These books show you how to reuse items, and problem solve.
2. Books on memory and accelerated learning. I try to cover most of the techniques here in my blog, but I might miss a few and there are hundreds of books out there on the art of memory and learning.
3. a novel. We learn from characters in books as they go about living in society and solving their problems. Novels are filled with great characters and learning experiences.
4. A book on argument fallacies. These include ad hominem, post hoc and hasty generalization. There are lots of these fallacies. As you read about them, look for examples in daily speech and news reporting.
5. A book of daily intellectual meditations. A fact a day. Sure if you are taking classes,and you already have enough to learn, but try to broaden your learning horizons with a book that gives you more. Some are in the form of fact a day calendars.Look at the daily word in dictionary.com
6. Your daily journal.
Of course, don't limit the books either in your kindle or on your book shelf. A writer friend of mine has a book on how to exit sinking ship. He says he has not had to use it for reference yet, but one never knows when one of his characters might have to exit a sinking ship. Of course, that book may not be available in Kindle yet. So we still have to keep some volumes on our shelfs.