Before superheroes made the jump to live-action, they joined the realm of cinema through animation. It makes sense that this was one of the first mediums in which the genre thrived, given the inherent similarities between animation and superheroes' native realm of comic books.
The ten earliest Marvel cartoons were aired on television long before the multiplexes and popular filmmaking as a whole were dominated by spandex-clad beacons of justice.
10 The Marvel Superheroes (1966)
The first animated Marvel adaptation was an anthology series simply titled, "The Marvel Superheroes." The series starred five of Marvel's foremost heroes: Captain America, Iron Man, Thor, the Hulk, and Namor The Sub-Mariner. 65 episodes, 13 for each hero, were produced and aired across the latter third of 1966, from September 1 to December 1.
The series was produced by Grantray-Lawrence Animation on the cheap, with limited animation usually taken directly from the comics which the episodes were adapted and voice acting more suited for radio. Still, the series was a breakthrough for Marvel and produced memorably corny themes still associated with the characters to this day ("When Captain America throws his mighty shield...").
9 Fantastic Four (1967)
The following year, Marvel's first family were the next to make the jump from comics in the eponymous series The Fantastic Four. This series, produced by Hanna-Barbera, aired longer than The Marvel Superheroes - one year from the September of 1967 to the same month next year.
However, only a fraction of the episodes were produced - 20. The series stuck close to the Lee/Kirby FF run story-wise, but the limited animation meant the series' aesthetic paled in comparison to the imaginative dynamism of Kirby's drawings.
8 Spider-Man (1967)
Begun the same year as Fantastic Four, Spider-Man had the longest shelf life of the 60s Marvel cartoons - it scored three seasons and 52 episodes, lasting until 1970. The series' first season was primarily based on the earliest Spider-Man issues by Stan Lee & Steve Ditko - featuring most of Spidey's comic adversaries but plenty of original ones as well, with the regular supporting cast of J. Jonah Jameson & Betty Brant.
Seasons 2 and 3 saw a change of pace - produced by Ralph Bakshi, the comic rogues gallery was shoved aside and the animation became more psychedelic. However, there were also budget cuts - as a result, many episodes featured recycled footage, either from contemporaneous Bakshi production Rocket Robin Hood or previous Spider-Man episodes.
7 The New Fantastic Four (1978)
The FF were the first Marvel characters to get a second turn at the bat with this 1978 cartoon. The series is most (in)famous for the absence of the Human Torch; due to rights issues, Johnny Storm was absent, replaced by H.E.R.B.I.E, a robot built by Reed Richards.
Between this and the meager 13 episode run, this is a series that has mostly faded from history and fans' memory, perhaps for the better.
6 Fred and Barney Meet The Thing (1979)
One of the oddest cartoon crossovers was this 1979 mash-up between the Thing (his third experience in animation had Ben Grimm without his fantastic friends) and a new incarnation of the Flintstones.
However, despite what the title might have indicated, the titular characters never met outside of the title sequence - instead, there were segments focused on the Thing and segments focused on the Flinstones, but they never crossed over.
5 Spider-Woman (1979)
By 1979, it wouldn't be long before Spider-Man returned to animation. Before he could do so, however, his distaff counterpart got a shot at her own eponymous cartoon. A 16 episode production by DePatie–Freleng Enterprises, the series altered the comics' Jessica Drew and those in her orbit to make her seem more of a direct analog to Spider-Ma.
Her origin and powers were more akin to the Web-Slinger's and her supporting cast exclusive to the show, while her day-job was as the editor of "Justice Magazine," (a la Peter Parker's work as a Daily Bugle photographer). Most interestingly, Paul Soles reprised his role as Spider-Man from the 1967 cartoon for a one-episode guest appearance.
4 Spider-Man (1981)
When Spider-Woman wrapped up, it was time for Marvel's first wall-crawling hero to make his full-time return to animation. The series mostly stuck to the basics, with Spider-Man's usual rogues gallery and supporting characters (J. Jonah Jameson and Aunt May) playing their expected roles.
However, the series also branched into the wider Marvel universe; Doctor Doom served as the series' most recurring villain, in addition to one-off appearances by Magneto & the Wizard. Furthermore, several episodes featured team-ups between Spider-Man and other heroes - Captain America, Medusa, Ka-Zar, and the Sub-Mariner. However, that latter concept wouldn't be explored in as much depth until next time out...
3 Spider-Man and His Amazing Friends (1981)
Airing simultaneously with the aforementioned Spider-Man cartoon, His Amazing Friends featured the Wall-Crawler alongside two Mutant heroes - Iceman and Firestar. Notably, this is the series that introduces Firestar; the creators had originally conceived of the Human Torch as the third end of the superhero triptych, but once again, rights complications kept Johnny from appearing.
Thus, Angelica Jones was born. Episodes tended to feature either "the Spider-Friends" facing off against one of the Wallcrawler's usual enemies, or teaming up with another Marvel superhero to battle a member of that hero's rogues gallery. Notably, due to Iceman's ties to the X-Men allowed two guest appearances by that team - this was the first time the team had appeared in animation under their proper name (they had guest-starred in a Sub-Mariner segment of The Marvel Superheroes, but were called "Allies For Peace.")
2 The Incredible Hulk (1982)
The next Marvel cartoon came in quick succession. This one starred the Incredible Hulk and debuted in 1982, the same year that the live-action Incredible Hulk tv series starring Bill Bixby wrapped up.
Airing alongside Spider-Man and His Amazing Friends, the animated Hulk was a more faithful adaptation of the comic than the preceding live-action series, with appearances by characters such as the Leader, the Abomination, and She-Hulk. Still, the series lasted a meager 13 episodes.
1 Pryde of the X-Men (1988)
The next Marvel animated project never made it past the pilot stage, yet served as a harbinger of things to come. "Pryde of the X-Men" featured the induction of Kitty Pryde (voiced by a young Kath Soucie) into the X-Men - consisting of Professor X, Cyclops, Storm, Wolverine, Colossus, and Dazzler. Kitty's welcome is interrupted by a plot by Magneto and his Brotherhood of Mutant Terrorists (Emma Frost, Juggernaut, Pyro, the Blob, and Toad) to plunge Earth into a new Ice Age.
Though the animation is impressive for its era, the pilot's overall simplicity shows the trappings of 1980s American animation. Despite the Chris Claremont influence, Magneto is a one-note evil-doer right out of the Silver Age; the rest of the cast doesn't fare any better. While "Pryde of the X-Men" didn't go to series, it would only be a few years before the X-Men's fortunes on TV would change for the better.