I assume we're talking about Robert Kirkman here, the main force behind the 'The Walking Dead' comics. Beyond that, he's got a pretty impressive backlist, honestly. His other big comic is 'Invincible', which is this superhero saga that's way more than it seems at first—less about capes and more about family drama and really messed-up consequences. He also co-created 'Outcast' with artist Paul Azaceta, which is a horror series about demonic possession. Then there's stuff like 'Super Dinosaur', which is exactly what it sounds like and a lot of fun, and 'Fire Power', a martial arts fantasy. He's got this knack for taking a genre and stretching it out over hundreds of issues to see what happens to characters long-term.
Honestly, 'The Walking Dead' is his most famous, but for my money, 'Invincible' is his masterpiece. The pacing is relentless, and the emotional beats hit harder because you grow up with the protagonist. I'd argue it's a more cohesive complete story than TWD, which kinda wandered later on. His other works share that same gritty, character-focused DNA, even if the settings are totally different.