Man, zombie media can be so hit or miss, but when it hits, you know it. The one that really cranked the tension for me wasn't a book at first, but the comic series 'The Walking Dead' by Robert Kirkman. The action is constant and brutal, but the real edge-of-your-seat stuff comes from the human conflict. You're never just waiting for a zombie to jump out; you're terrified of what the other survivors might do next.
I tried the novels, like 'World War Z' by Max Brooks, and while that's an absolute classic for scope and detail, it's more of a chilling historical account. For relentless, in-the-trenches action, I keep going back to 'The Living Dead' by George Romero and Daniel Kraus. It starts fast and just... doesn't let up. The scale feels huge, but you're glued to these individual fights for survival that are just exhausting in the best way.
Honestly, I sometimes skim the slower, 'character reflecting on loss' parts in other stories, but those books made me read with the lights on.