One of my all-time favorite books with a tiny, magical protagonist is 'The Borrowers' by Mary Norton. It’s not exactly a fairy, but Arrietty Clock and her family are miniature people living under the floorboards, borrowing items from humans to survive. The whimsical world-building and Arrietty’s adventurous spirit always reminded me of fairy tales.
Another gem is 'The Fairy Rebel' by Lynne Reid Banks, where a rebellious fairy named Tiki defies the evil queen to help a human couple. The mix of humor and heartwarming moments makes it a standout. I reread it last summer, and the nostalgia hit hard—Tiki’s bravery still feels so fresh!