If you're into gritty, lone-wolf protagonists with a dark past like Evan Smoak in 'The Last Orphan', you might want to check out 'Orphan X' by Gregg Hurwitz—same series, so it’s a no-brainer! But if you’re craving something fresh yet similar, try 'The Gray Man' by Mark Greaney. It’s got that same relentless pace, morally ambiguous hero, and high-stakes action.
For a twist, 'I Am Pilgrim' by Terry Hayes blends espionage with a cerebral cat-and-mouse game. Or dive into 'The Terminal List' by Jack Carr if you prefer military precision with revenge themes. Honestly, once you start this genre, it’s hard to stop—there’s always another shadowy operative waiting in the pages.