You can find itafushi fanfic on some popular fanfiction websites like Archive of Our Own (AO3). There are many users who contribute their creative works about itafushi there.
One great itafushi fanfic could be 'ItaFushi's Adventure in the Mysterious Realm'. It has an engaging plot where Itadori and Fushiguro embark on a journey filled with magic and mystery. They face challenges together and their friendship deepens throughout the story.
For instance, there's a story where Birbal proved the honesty of a servant to Akbar. Another one is when he helped Akbar understand the value of kindness through a unique situation.
Alien comics usually focus on extraterrestrial themes and creatures, while all-in-one comics might incorporate a variety of genres and storylines. That's a big difference.
Well, manhwa is Korean comics and corn is a type of crop. There's really no obvious relationship between the two. Maybe in some very specific and rare context there could be, but generally speaking, they're completely different things.