For thriller, I always recommend Dean Koontz. He mostly writes suspense thrillers, and I find his books very effective thrillers. The first book I ever read of his was Watchers, and it got me hooked on his works. Koontz also has many other books, including Strangers, Twilight Eyes, Darkfall, Lightning, Phantoms, etc. (Since I don't know your age, I will warn that most of Dean Koontz's books do contain some adult themes and scenes.)
Best wishes!