Kirsten Miller has written another Kiki Strike novel called Kiki Strike: The Empress’s Tomb. Here are a few more titles you might enjoy:
Gregor the Overlander by Suzanne Collins.
When eleven-year-old Gregor and his two-year-old sister are pulled into a strange underground world, they trigger an epic battle involving men, bats, rats, cockroaches, and spiders while on a quest foretold by ancient prophecy. The first book in the Underland Chronicles.
Skulduggery Pleasant by Derek Landy.