Dungeon Crawler Carl — Matt Dinniman's series about a man, his princess-named cat, and the most lethal televised death sport in galactic history — has become the defining "why is this so good" moment in LitRPG. It's darkly funny, brutally difficult, structurally inventive, and emotionally honest in ways that catch readers completely off guard. The books are long and they are still the most talked-about series in the genre.
If you've finished what's available and you're looking for what to read next, you're probably looking for some combination of: a sarcastic or deeply human protagonist, a system that wants to kill you rather than accommodate you, humor that doesn't undercut genuine stakes, and forward momentum that never stops. Possibly also a scene that makes you unexpectedly emotional about a cat.
Nothing on this list is exactly like Dungeon Crawler Carl. These are the books most likely to scratch a similar itch — each for a different reason. Top picks: He Who Fights With Monsters (Jason Cheyne) for the culture-clash humor and momentum; Defiance of the Fall (J.F. Brink) for relentless multiverse survival; The Primal Hunter (Zogarth) for immersive office-worker-turned-powerhouse progression; and Apocalypse Breaker by Aaron Renfroe for fast-paced system apocalypse with real character stakes.