If you loved the magical boarding school vibes and intricate world-building of 'Keeper of the Lost Cities', you’ll probably adore 'The School for Good and Evil' by Soman Chainani. It has that same blend of fantasy, friendship, and high-stakes adventure, but with a darker, fairy-tale twist. The way it plays with destiny and moral ambiguity is so gripping—I binged the whole series in a week! Another great pick is 'Percy Jackson and the Olympians'. While it’s more mythology-based, the found family dynamics and protagonist’s journey of self-discovery feel really similar. Plus, the humor and action are top-notch.
For something with a sci-fi edge, 'Skyward' by Brandon Sanderson might hit the spot. It’s got a young, determined protagonist like Sophie, but in a futuristic setting with spaceships and alien battles. The emotional depth and pacing are just chef’s kiss. And if you’re into puzzles and hidden societies, 'The Mysterious Benedict Society' is a must. The cleverness of the kids and the heartwarming teamwork totally reminded me of the Keeper series. Honestly, any of these could fill that post-Keeper void—I’ve reread them all multiple times!