ReBoot debuted in 1994 as a product of a Canadian animation company called Mainframe Entertainment. At the time, ReBoot's animation was cutting edge as it was billed as the first entirely computer generated cartoon series. Even though much of the animation looks clunky and antiquated today, the writing is fresh and inspired. The series takes place inside a computer with many of the series' initial humor being derived from computer puns (the female lead's name is Dot Matrix and the antagonists are viruses named Megabyte and Hexadecimal.) The most remarkable feature about the show is how after a fairly mediocre first half of season one, the show starts to escalate in tension, humor, characterization, and narrative storytelling. By the time season 2 comes along, full narrative arcs are being constructed and season 3 gets so dark that the show is barely recognizable from its humble, happy beginnings. If you can get past the dated animation the writing will captivate you.
2. Beast Wars: Transfomers
Way before Michael Bay brought the Transformers to the big screen alongside Megan Fox and Shia LaBeouf, there was the 1980's original generation cartoon series. Though it was unabashedly used to sell toys, it actually provided some decent storytelling for kids. Transformers fell out of popularity, as most fads do, but toy company, Hasbro hoped to repeat the success in the mid 1990's with a new line of toys. Instead of vehicles turning into robots, these Transformers would be "robots in disguise" as animals. The TV show that accompanied it was, like ReBoot, also produced by Mainframe Entertainment, and it is exceptionally well done. Beast Wars: Transformers' first season is episodic with no governing story line; it's just an ongoing battle between the heroic Maximals, and the villainous Predacons. Subtle hints at something larger are sprinkled through the season until everything goes to hell at the end. From there, seasons 2 and 3 feature story arcs that are as tightly written as the best seasons of Breaking Bad. Helping the show even more is an exceptional cast of voice actors that add a great deal of personality to the heroes and villains alike.
3. Teenage Mutant Ninja Turtles (1987)
At the time of this writing there have been three Teenage Mutant Ninja Turtles cartoons, the most recent of which is presently airing on Nickelodeon. The original 1987 version though is the one that's the most iconic; and it's a beautiful mess. The first season of the show is only five episodes long, and there are so many animation errors that it's mind boggling. Sometimes the wrong turtle is wearing the wrong color, the wrong voice is coming out of the wrong mouth, and there's a stupefying amount of awful background animations. But, the show is often genuinely funny, much of the action is surprisingly strong, and there are some actual recurring story elements; a unique aspect to a Saturday morning cartoon. Later seasons iron out the animation problems, leading to a more carefully crafted cartoon. It's an iconic show for a reason and even if it's one of the weaker shows on this list, it's still worth your time.
4. Swat Kats: The Radical Squadron
There's a good chance you're not familiar with this short lived Hanna-Barbera cartoon that ran from 1993 - 1995. During the mid '90s, the company responsible for Yogi Bear, The Flintstones, The Jetsons, Scooby-Doo and numerous other iconic shows and characters was trying to update itself for the times, and Swat Kats was part of it. The episodes follow the crime fighting exploits of T-Bone and Razor, two former combat pilots who were drummed out of the air force after being forced to take the blame for an operation gone wrong. Undeterred in their desire to protect their home, they get jobs at a junkyard and build their own jet and weapons from the salvage that comes their way. Also, everyone is an anthropomorphic cat. This stands in stark contrast to the fact that this show is pretty damn dark, with tertiary characters being killed off quite a bit; something that according to various fan sites, may have been what led to its cancellation. Swat Kats only looks childish but don't let its feline cast fool you, this cartoon has action and personality bursting out of the seams.
5. The Real Adventures of Jonny Quest
The 1960's cartoon, Jonny Quest is well known among fans of classic animation for being a uniquely inspired take on classic sci-fi and adventure serials and adapting them to a cartoon format. In subsequent years it has been referenced, parodied, and paid homage to countless times. The most prominent of these is the heavily referential The Venture Bros, which is also responsible for bringing the old Hanna-Barbera property back into public consciousness. There was an attempted revival of the brand in 1996 when the various Turner Networks (Cartoon Network, TNT, TBS, etc.) premiered The Real Adventures of Jonny Quest. Advertising for it was massive and the show was greatly hyped for its blending of traditional and computer animation. Naturally, it's the hand drawn animation that has stood the test of time but more importantly, so have the stories. Like the aforementioned Swat Kats, this iteration of Jonny Quest was darker and grittier. It featured the titular young hero, adopted brother Hadji, their father Dr. Benton Quest, body guard Race Bannon and his daughter Jessie Bannon, taking on some pretty serious threats to themselves and the world. Take for instance the memorable villain, Ezekiel Rage; a former U.S. government agent who was abandoned by his bosses after his cover was blown and subsequently nearly killed in a car crash. His wife and daughter weren't so lucky though and Rage became twisted with....well...rage. It's an intense subject matter for a kid's cartoon, and considering all the supernatural and conspiratorial plots that the episodes have, it's probably the closest we've ever come to an animated version of The X-Files.
6. The Real Ghostbusters
When you have the future creator and writer of the sci-fi series Babylon 5, J. Michael Straczynski as one of your main writers and story editor, you know you're not exactly making a run of the mill kid's show. The Real Ghostbusters had a wildly successful run from 1986 - 1992 and is one of the few cartoon properties to do justice to the live-action source material it was taken from. Just like the film, the cartoon blends comedy with dark supernatural drama. The Ghostbusters do battle with everything from the Sandman to the Babylonian god, Tiamat. The only quibble is the forced addition of the ghost Slimer, something that was obviously tone to make the show more "kid friendly." As a result, the cartoon does suffer a bit from his presence, but not enough to detract from its overall quality. If you really want something to tide you over until the female Ghostbusters reboot, this is your fix.
7. Batman: The Animated Series
This is a painfully obvious addition to the list for those who have seen the show, but in case you are one of the uninitiated, this is a must see. In 1992 Bruce Timm changed the face of children's cartoon programming by delivering an animated version of Batman that was not quite as dark as the Tim Burton Batman and Batman Returns films of that time, but were as close as you could get and still be broadcast to kids. Timm brought together art deco and film noir, stylized it with some modern flourishes, and created a richly detailed Gotham City for the Caped Crusader to fight crime in. Film composer Shirley Walker was brought in to oversee that every episode had it's own orchestral score, and voice director Andrea Romano helped find actors and actresses to bring the people of this world to life. She once described her process not as finding "character voices" but as finding "voices with character." The result of this is arguably the definitive take on Batman and The Joker as provided by Kevin Conroy and Mark Hamill respectively. This show is responsible for bringing so much to television and the Batman mythos that it would require its own article to fully detail it all. Considering that Batman is bigger than ever thanks to the Christopher Nolan trilogy and the upcoming Batman vs. Superman film, if you haven't watched this cartoon, now's the time to do so. You will not regret it.