Depends what you like but I’ve enjoyed the Orpan X servers by Gregg Andrew Hurwitz
The Nowhere Man is a legendary figure spoken about only in whispers. It’s said that when he’s reached by the truly desperate and deserving, the Nowhere Man can and will do anything to protect and save them.
But he’s not merely a legend.
Evan Smoak is a man with skills, resources, and a personal mission to help those with nowhere else to turn. He’s also a man with a dangerous past. Taken from a group home at twelve, Evan was raised and trained as part of the Orphan Program, an off-the-books operation designed to create deniable intelligence assets—i.e. assassins. Evan was Orphan X. He broke with the program, using everything he learned to disappear and reinvent himself as the Nowhere Man.
But those behind the Orphan program refuse to let go of their asset…
"[Orphan X is] the most exciting thriller I’ve read since The Bourne Identity. Fans of Jack Reacher, Mitch Rapp, and Jason Bourne will LOVE Evan Smoak, and the deadly, secret world of the Orphan Program. A new thriller superstar is born!" --#1 New York Times bestselling author Robert CraisLess