Saga of Swamp Thing 21 The Anatomy Lesson by Alan Moore reimagines what Swamp Thing actually is. A true horror story and the start of a great series.
The New Teen Titans, Who is Donna Troy, by Wolfman and Perez has Dick Grayson as detective, discovering Donna Troy’s early life.
Batgirl 2009, issue 14, has Stephanie Brown as Batgirl team up with Supergirl on a girl’s night out on a college campus, where Dracula and other vampires come out of a movie and the two team up to rid the world of these monsters. Not serious at all, just great fun.
Detective Comics #826. It’s a simple premise and not any kind of big, epic, game-changing story arc, but the pacing and tension are absolutely flawless. It’s the best Joker story I’ve ever read. Heck, it’s the best story I’ve read in a comic book, full stop, and I’d rank it up there with Almost Got 'Im from Batman: The Animated Series as one of my favorite superhero stories in any media.
Now I feel like I’m overselling it, but it’s a really good story is all I’m saying.
Stand alone stories are uncommon today. Superman Annual #11 is certainly one the best. The Flash #134 (Mark Millar, Grant Morrison, Paul Ryan, John Nyberg) from 1998 was also one of my favorite stand alone stories.
Flash 123 (Flash of two worlds) It is the “Big Bang”of the multiverse. No bigger, more important concept in the history of DC comics.
2nd on the list is Gotham by gaslight. It shows not just the true versatility of Batman (DC’s most iconic hero. No dis on the house of El) Batman is the most resilient of them all. Only one to be in continuous monthly publication since his inception 80 years ago. (Recall the few months of no Supes before Man of Steel launched) Also Gotham by gaslight is the birth of elseworlds. There would be no Watchman and the others without it.
Are they “the best” script or artwork…well best is always arguable. There is no doubt, through the entirety of DC’s history, they are the most significant. Both are brilliant stories that took massive leaps into the unknown and seared their ideas into the frontal lobe of DC forever.