Manga based on Marvel properties have been actively published since the 1970s, and this stack aims to collect all the Marvel titles that are included in the MAL database, as well as provide information on those that have not yet been added. All titles are listed in order of release. If you're surprised to see Big Hero 6 here, here is the answer to your confusion and the reason for its inclusion: the Disney animated film is based on the Marvel comic book series.
Titles missing from MAL:
- Spider-Man (1978-1979) [the infamous tokusatsu series had four manga adaptations published in different magazines; each of them needs its own entry]
- Moon Knight (1979-1980) [pending approval: https://myanimelist.net/manga/160556/Mu-n_Naito]
- Psychonauts (1993) [Marvel/Nihon Shuppan collaboration]
- X-Men (1994-1995) [light novel series]
- X-Men (1994-1995) [another manga series based on the X-Men animated series]
- Blade: Trinity (2005) [one-shot manga by Takashi Okazaki bundled with the deluxe version of the film's soundtrack]
- Avengers (2014) [one-shot chibi manga by Fujiminosuke Yorozuya]
- Attack on Avengers (2014) [Avengers/Attack on Titan crossover; pending approval: https://myanimelist.net/manga/134136/Attack_on_Avengers]
- Baymax (2014) [two-chapter manga prequel to the film; not the same that we have on MAL]
- Avengers: Age of Ultron Episode 0 (2015) [pending approval: https://myanimelist.net/manga/154477/Avengers__Age_of_Ultron_Episode_0]
- Tony to Mutta (2016) [Iron Man/Space Brothers crossover
- Doctor Strange: Episode 0 (2016) [one-shot, non-canonical prequel to the film]
- Cloak of Levitation Goes Out (2017) [licensed web manga series by Haruichi]
- Meisho Manga Realization Featuring Marvel's Samurai Heroes (2018) [based on a toyline]
- Marvel Meow (2019)
Japan wasn't the only Asian country to have its own original Marvel media. South Korea had Avengers: Electric Rain (2014-2015) and Avengers K (2015-2016) manhwas, and China produced two manhua series titled Warriors of Three Sovereigns and Aero, both 2018-2019. None of them are documented on MAL.
Marvel has also published comics based on several franchises of Japanese origin, but though they don't belong on MAL, they're worth mentioning here at least for the sake of completeness. These include Godzilla (1977-1979), Shogun Warriors (1978-1980), Zoids (1986-1987), several Power Rangers titles (1995-1996), Rise of Incarnates (2014-2015) and several Ultraman titles (2020-present; includes an Avengers crossover). Malibu Comics, acquired by Marvel in 1994, published a Street Fighter miniseries in 1993. Digging even deeper, it's also worth mentioning Transformers, given the franchise's Japanese roots (roots, bloody roots!) – Marvel helped to cement the Transformers lore and published five comic book series from 1984 to 1994, as well as a crossover with the New Avengers in 2007.
A few interesting facts. Marvel published Akira in the US as a colored 38-issue comic. They also reprinted the Star Wars manga. And now the most obscure: Marvel's Italian branch in its last years published translations of such manga as Berserk, Evangelion, Slam Dunk, Battle Angel Alita, Silent Möbius, Martian Successor Nadesico, Dark Angel, Slayer, Shoma, Eat-Man and Tenchi Muyo.
Feel free to contact me if I missed something or if any manga from the missing list was added to the MAL library.
P.S. BTW, after all these years I still hope that someone will translate the Hulk manga, lol