One must - read fiction thriller is 'Gone Girl' by Gillian Flynn. It has a complex plot full of twists and turns. The characters are well - developed, and the story keeps you guessing until the very end. Another great one is 'The Girl with the Dragon Tattoo' by Stieg Larsson. It combines mystery, thriller, and some dark elements that are really engaging.
I would highly recommend 'In the Woods' by Tana French. It's a beautifully written thriller that delves deep into the past and how it affects the present. The mystery is full of suspense, and the Irish setting adds an extra layer of charm. 'Sharp Objects' by Gillian Flynn is also a must - read. It has a dark and disturbing plot that will keep you on the edge of your seat as you try to figure out what's really going on.