Batman, that’s too basic an answer, but the honest truth is that the Trinity is my fav thing about DC. I love Superman and Wonder Woman, the latter who doesn't get enough love, in my opinion. She hasn’t gotten as much mainstream classic stories like the first two. I love Gail Simone’s run and George Perez’s classic one, too. But she doesn’t have iconic titles like Batman’s The Dark Knight Returns, or The Long Halloween, The Killing Joke or even Under the Red Hood. Superman has a few although I was always say it’s ironic most of his iconic stories are all different version of his origin or death. Birthright, All Seasons, All Star Superman, Death of Superman, etc.
I think western comics need to transition even more fully into novel approaches and have titles like that that become iconic, that anyone can pick up and read and have a good story. All those I named remain their bestsellers. Why do you think Watchmen remains one as well? Because it’s just the one big book they read and done, not having to track 75 years of history and issues and continuity….anyway, I kinda fell off my point there lol. But yeah, the Trinity is my fav of DC, and I think they need more isolated stories like that. That’s my two cents.