The Flash has been one of the most enduring characters of the DC Comics Universe. The 2000s was a significant era for the development of the character's third incarnation, Wally West. Apart from limited series and one-shots, the scarlet speedster had a great run on The Flash Vol 2 that was chiefly written by Geoff Johns and drawn by Scott Kolins.
This volume is much acclaimed among fans and even inspired several episodes of the ongoing CW series The Flash. Towards the later years of the decade, Barry Allen also made an appearance with the miniseries Rebirth leading to far-reaching consequences for the character's future in comics.
Final Crisis: Rogue's Revenge (Limited Series)
A three-issue series within the Final Crisis crossover, the titular Rogues in this particular storyline actually do the good this time. The Flash comic book villains Heat Wave, Captain Cold, The Weather Wizard, and Mirror Master join forces to defeat the villain Libra for tricking them to work for Darkseid. Another mission includes seeking revenge for Bart Allen's death at the hands of his own clone Inertia.
It is an interesting take on the anti-heroic Rogues while also welcoming Barry Allen. In fact, it's Allen's return in Final Crisis that led to The Flash: Rebirth and subsequent watershed moments in DC comics.
The Wild Wests (The Flash Vol 2 #231-237)
The Wild Wests finds Wally West and his two speedster children returning to Keystone City after a tumultuous battle with Superboy-Prime. However, their troubles have only started as Wally finds out that his sidekick Kid-Flash has been murdered.
Having started out early as a superhero himself, Wally is often concerned about the wellbeing of his younger proteges. And this murder shakes him to the core as he figures out the mystery. This personal arc won over audiences not just because of its narrative but also because it marked the return of Mark Waid, the writer who penned numerous Flash comic issues in the 1990s.
The Flash: Rebirth (Limited Series)
This six-issue limited series marked the perfect start for a new era as the decade had wrapped up with The Flash Vol 2. With Barry Allen returning from the dead in the Final Crisis crossover event, Rebirth adds more context to his new journey. He encounters all speedsters in the history of the Flash universe, ranging from allies like Wally West to villains like Savitar.
The adventures aside, it is certain that Barry Allen is back for good. The 'rebirth' of the character was celebrated among comic book fans and the series set a benchmark for future storylines involving Barry Allen, including the TV adaptation.
Wonderland (The Flash Vol 2 #164-169)
Wally West finds himself weak and powerless as he gets transported to a parallel version of Keystone City, courtesy of Captain Cold and Mirror Master. Further, he also gets teleported to historical eras such as the French Revolution.
All in all, Wonderland is quite a fever dream and lives up to its name. The usually valiant Wally becomes the confused and naive Alice as he goes down the rabbit hole of Mirror Master's 'mirror world.' A major reason for fans to check out this arc is also the fact that it marked Geoff John's debut as a writer for The Flash.
Blackest Night (Crossover)
Blackest Night is an emotion-driven storyline that features the personified force of death called Nekron. This spirit-like creature reanimates dead bodies and then takes out all the emotion of the revived souls. Nekron's actions lead to the revival of several Green Lanterns and turn them into his own team of minions, the Black Lantern Corps.
Even though it's majorly a Green Lantern comic issue, a revived Flash (Barry Allen) also makes a major appearance in fighting off the Black Lanterns. Even Professor Zoom becomes one of the Black Lanterns increasing the stakes for Allen.
Blitz (The Flash Vol 2 #192-200)
Gorilla Grodd is out of prison leading Wally West to the rescue. Meanwhile, Hunter Zolomon aka the Reverse-Flash returns to destroy not just West but also his family. What follows is a lot of hand-to-hand combat between the two speedsters, and of course, a lot of running.
As Zolomon plans to kill a pregnant Linda, the comic reveals his ruthlessness. As for Wally West, he struggles to fight him off thinking about Zolomon's past. Once a close friend and an FBI profiler, his tragic backstory adds further to his character development.
Ignition (The Flash Vol 2 #201-206)
Ignition deals with a brainwashed Wally West who is slowly 'relearning' his powers. But he needs to get back to his former self quicker as Keystone City is riddled with crimes. Even though Captain Cold seems like the most likely perpetrator, the antihero claims that there is someone else.
The storyline makes for an interesting read as Wally realizes his own worth as the fastest man alive. As he tries to master his superspeed once again, he goes through phases of self-introspection to figure out the true extent of his powers. With Captain Cold's innocence, Ignition also shows how he is much more than just a one-dimensional Flash villain.
Blood Will Run (The Flash Vol 2 #170-176)
In Blood Will Run, The Flash encounters a murderous cult that goes on to kill everyone that Wally has ever saved. A personal angle is thrown in the mix when Wally's old flame Magenta is also a part of this cult.
The story arc shows how it is difficult for superheroes to settle down with normal lives. In the start, Wally seems to be content with his wife Linda but when two former lovers (Magenta and Jesse Quick) return to his life, chaos ensues yet again. In fact, Jesse's name is also on the hitlist of the cult. Such events hardly give Wally any time to breathe.
JLA/Avengers (Limited Series)
The biggest heroes of the Marvel and DC pantheon face off against each other in this larger-than-life four-issue miniseries. Even though the Avengers and the Justice League do ally with each other later on, their massive battle in the opening issues makes for some iconic panels.
In The Flash's case, he faces off against Marvel's own speedster Quicksilver. An adrenaline-fueled battle between these runners is difficult to envision on the big screen. Of course, fans of The Flash would be more than delighted to find him fighting it out with the lightning-fast mutant.
Iron Heights (One-Shot)
When compared to the other Geoff Johns stories in The Flash series, Iron Heights is quite darker. The one-shot is set in the titular prison as the scarlet speedster aims to prevent a viral outbreak caused by a homicidal surgeon. Darker secrets await him as the imprisoned Rogues Gallery runs away with the surgeon.
The primary antagonist in the series is Dr. Michael Amar, a man who became a spree killer to stop the voices in his head. As the Flash seeks to interrogate him, he's shocked to find Amar sewing his own mouth shut. This particular moment has to be one of the darkest panels of Flash comics.