The Draygon books I've been working on came while I was binge playing Dragon Age Inquisition. Now it's been so long I can't remember what my original idea was, but as I actually wrote it the first book evolved well beyond Dragon Age so now the only resemblance of the game is I have a version of tranquil mages. I call them the Vanguard Mages and they're forced to wear bracelets that zap them of all freewill and thought.
I had another book called Lady of the Mysts that was inspired by the Aes Sedai in Wheel of Time. That one ended up staying a little TOO similar to the Aes Sedai for my liking so it needs to go through some major rewrites at some point so it no longer looks like an out right copycat.
The final book that was directly inspired by something is a book called The Thirteenth Day. I was reading the Raven Cycle books and really liked the Ghost character in it. Made me think about what would happen if he wasn't actually dead but just trapped while his body was dying. I know that story has actually been done a million times before in both books and movies, but it's still what I wanted to write. So I wrote a kind of love story where the boy could see ghosts and was supposed to use his ability help them crossover. But the girl ended up not being a ghost, just treading that thin line of life and death.