The 2000s are a decade that people originally weren’t supposed to see. At the turn of the century, it was thought all the world's computers were going to crash due to the infamous Y2K bug. Instead, the decade introduced us to trends that defined the new millennium: frost-tipped hair, plain white t-shirts, and innovative cartoon shows.

The aughts, as fans have come to know them, would usher in a new era in cartoons. While the Looney Tunes and other animated shows were still popular with kids, the 2000 cartoons would open the door for more adult humor to make its way into the animated universe. The best cartoons from the 2000s can often inspire nostalgia with their simplicity and iconic characters that represent a long-gone era.

12 'Danny Phantom' (2003 - 2007)

Creator: Butch Hartman

Some regard Danny Phantom as one of the last great cartoons Nickelodeon produced, and with good reason. It’s a stellar entry among the early 2000s cartoons, coming from Butch Hartman (the guy behind The Fairly Odd Parents) that mixes humor and action well for a pre-teen audience.

The show follows Daniel “Danny” Fenton (David Kaufman), a teen who accidentally turns himself into a half-ghost, becoming the titular superhero, "Danny Phantom.” If there is one criticism of this show, it’s that it had too short of a run, lasting for just three seasons.

Watch on Paramount+

11 'Kim Possible' (2002 - 2007)

Creators: Bob Schooley, Mark McCorkle

Any fan's early aughts childhood was not complete if they didn’t watch Kim Possible every week – it's hard to believe it's one of the old cartoons from the 2000s now. The show follows the life of Kim Possible (Christy Carlson Romano), a high school student who is also a crime-fighter. Along with her sidekick and best friend Ron Stoppable (Will Friedle) and his pet mole-rat Rufus, the trio keeps the town of Middleton, USA safe from the dark corners of humanity.

Like Nickelodeon’s Danny Phantom, Kim Possible had a great mix of comedy and action that stayed suitable for the audience it was geared towards, and is, to this day, one of the best cartoons produced on the Disney Channel.

Watch on Disney+

10 'Fillmore!' (2002 - 2004)

Creator: Scott M. Gimple

For a long time, this Disney cartoon was largely forgotten; but hardcore fans remember Fillmore. The series follows Cornelius Fillmore (Orlando Brown), a 12-year-old who joins the safety patrol after being “arrested” for stealing a shipment of chalk.

A parody of the police procedural dramas of the '70s, Fillmore had a great voice cast and premise that kept both young and older audiences engaged with its plot. It truly was a shame that it only lasted 26 episodes, and the show could use a movie to give the show the ending it truly deserved.

Watch on Disney+

9 'Ben 10' (2005 - 2008)

Creator: Man of Action

When Ben Tennyson (Tara Strong) stumbles upon the powerful Omnitrix, his life literally changes as he gains the ability to transform into a variety of alien creatures with unique powers in Ben 10. Alongside his cousin Gwen (Meagan Smith) and Grandpa Max (Paul Eiding), the young protagonist must master his newfound skills to stop an ever-growing threat of extraterrestrial villains.

With Ben 10's wonderfully designed aliens, each more interesting than the last, and equally compelling characters, the show is a fantastic reminder of the excitement of viewers' childhoods. Every episode brings new thrilling adventures as Ben battles increasingly dangerous antagonists, and rewatching them today still carries a taste of those exhilarating moments.

Watch on Netflix

8 'The Fairly OddParents' (2001 - 2017)

Creator: Butch Hartman

For fans of old 2000s cartoons, it may feel like The Fairly OddParents ended just yesterday, and the series is still alive in audiences' hearts. It follows a seemingly ordinary boy, Timmy Turner (Tara Strong), whose life is never the same when he learns he has fairy godparents – Cosmo (Daran Norris) and Wanda (Susanne Blakeslee).

The Fairly OddParents depicts the trio's misadventures as the godparents grant Timmy's desires through their magical powers, which, of course, often have unintended consequences. With vibrant animation to complement its clever humor (that mixes in a few life lessons), it's the perfect cartoon to watch as a kid that still needs to learn patience, hard work, and the true value of things.

Watch on Paramount+

7 'The Grim Adventures of Billy & Mandy' (2001 - 2007)

Creator: Maxwell Atoms

This hilarious Cartoon Network show had a very wacky premise. A dimwitted boy, Billy (Richard Steven Horvitz), and a cynical girl, Mandy (Grey DeLisle), "befriend" the Grim Reaper (Greg Eagles) by beating him in a limbo contest and putting him in eternal servitude.

First premiering as a segment on the Grim & Evil Show, The Grim Adventures of Billy & Mandy found its audience and paved its path as one of the network’s best cartoons of the decade. Though a largely forgotten 2000s cartoon – except for hardcore fans – it’s worth going back to check out what this show was an animated masterpiece of dark comedy.

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6 'Star Wars: Clone Wars' (2003 - 2005)

Developer: Genndy Tartakovsky

Today, it’s common to see Star Wars shows on streaming services, but in the early 2000s, there was one series that truly bridged the gap of the latest Star Wars universe: Star Wars: Clone Wars. Serving as an interquel to Episodes II and III, Clone Wars follows Obi-Wan Kenobi (James Arnold Taylor) and Anakin Skywalker (Mat Lucas) as the Galactic Republic begins the fall under the weight of intergalactic warfare and the Sith.

Visually stunning and with a riveting storyline, Star Wars: Clone Wars made it possible for George Lucas’ space opera to be told on the small screen with the same zeal and action found in the films. It remains one of the best Star Wars TV shows that's worth rewatching again today.

Watch on Disney+

5 'Teen Titans' (2003 - 2006)

Creator: Glen Murakami

Thanks to its endless reruns on Cartoon Network, it seems that Teen Titans Go! is the more mainstream adaptation of DC Comics' crime-fighting group. However, its predecessor is often hailed as the superior cartoon.

Debuting on Cartoon Network in 2003, Teen Titans was a successful adaptation of the comic book series and was one of the more popular shows on the network for its five seasons. The series came to an end in 2006 and was subsequently rebooted as Teen Titans Go. The new series was more oriented towards a kiddie audience, much to the grumbling of fans of the original series.

Watch on Prime Video

4 'Invader Zim' (2001 - 2006)

Creator: Jhonen Vasquez

The premise of Invader Zim was this: a little alien named Zim (Richard Steven Horvitz) wanted to show how big and bad he was by conquering the Earth, only for numerous obstacles to get in his way of achieving his ultimate goal.

While that may seem light on the surface, this Nickelodeon cartoon was deeper and darker than what its premise hinted at. The animation was top-notch, and the series had that perfect mixture of comedy, action, and sci-fi, with some horror elements thrown in there to keep the older crowd entertained. While the premise was quirky and silly, Invader Zim's shockingly dark episodes presented several storylines that constantly pushed the boundaries of its absurd nature.

Watch on Prime Video

3 'Samurai Jack' (2001 - 2017)

Creator: Genndy Tartakovsky

Words cannot express how visually beautiful Samurai Jack was. Premiering on the Cartoon Network in 2001, Samurai Jack was a principal showcase of just how innovative the showrunners at the network were in creating original content. The masterpiece follows a samurai prince (Phil LaMarr) who gets flung into the far future by the evil demon Aku (Mako) where he reigns supreme.

Called "Jack" by the denizens of the future, this nickname becomes the adopted name of the prince, and Samurai Jack fights to overcome obstacles to defeat Aku once and for all. After its initial run, Samurai Jack got a revival in 2017 that wrapped up its sweeping storyline. Once it was done, it was a sad farewell to a beautifully animated show that carved out its legacy.

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2 'Futurama' (1999 - )

Creator: Matt Groening

What would you do if you accidentally slipped into a cryogenic capsule and woke up 1,000 years into the future? That’s the premise behind Futurama, the Fox animated sitcom that found Philip J. Fry (Billy West), a down-on-his-luck pizza boy, thrown off into the far-off year of 2999.

Futurama is the quintessential workplace sitcom, where the humor of the show is found in the fledgling shipping company Fry works for in New New York. Futurama also gave fans Bender (John DiMaggio), the crass, cigar-smoking robot that provides the perfect sidekick to the delivery boy.

Watch on Hulu

1 'Avatar: The Last Airbender' (2005 - 2008)

Creators: Michael Dante DiMartino, Bryan Konietzko

Before the movie tarnished its reputation, Nickelodeon’s Avatar: The Last Airbender was – in all respects, still is – hailed as one of the greatest animated cartoons ever to air on network television. The series' main premise is that the world is filled with “benders,” people who can manipulate and control one specific element through telekinesis.

While the four nations (Water, Earth, Fire, and Air) are usually in harmony, it’s broken when the Fire Nation launches a campaign to take over the world. Only Avatar Aang (Zach Tyler Eisen), who can master all four elements, can restore balance to the world. With gorgeous animation and a mature, engrossing storyline, Avatar: The Last Airbender deserves to be called the greatest animated show the 2000s ever produced, and still holds up incredibly well today.

Watch on Netflix

NEXT: Strongest Benders in 'Avatar: The Last Airbender, Ranked'