Mine are fairly literal LOL
Guardian of Calandria - a book about the last gasp Guardians of a place called Calandria
Draygon Frost - This one is still literal but not as obvious until reading it. The MC has frost magic and she's the heir to the throne of Draygon, and Draygon is also her magical race. The sequel Draygon Inferno gets the Inferno part because the other main character has fire magic and if he doesn't learn how to control it he could burn the whole world. The third book will be Draygon Ashes but I haven't written enough of it to know if the Ashes part will truly play into the book or if it's just something my brain is all "this sounds cool" and I wind up changing it when I've written more of the book
I opted to use Draygon in all 3 book titles as a means to make it an obvious connection between the 3 books.
I'm not sure when I'll be ready to bring it to Tapas but Lady of the Mysts is about magical woman who are called the Ladies of they Mysts. The MC's best friend will be taken by them early on in the book because she has the "spark" that makes her one of these Ladies and that in turn draws him into the entire plot.
I usually lean toward the more obvious titles and they often have something to do with the MC of that book or what happens in the book.