The Shriek can be really interesting in fanfiction. Her sonic powers can be explored in unique ways, like how she uses them not just for destruction but also to manipulate situations or people around Spider - Man.
The Green Goblin is very popular. His chaotic nature and personal vendetta against Spider - Man make for great storytelling in fanfiction.
Doc Ock is a likely villain in Spider - Man angry fanfiction. His mechanical arms and his intelligence make him a formidable foe. His evil plans usually put the city in danger, and Spider - Man would be extremely angry trying to stop him. Also, Electro could be a villain in such fanfictions. His ability to control electricity can cause a lot of destruction, and Spider - Man would be angry at his disregard for human life while causing chaos.
Green Goblin is very memorable. His crazy laugh and the flying glider make him stand out. He has a complex relationship with Spider Man as Norman Osborn is also connected to Peter's personal life.
The Joker would be a great addition. His chaotic nature would contrast well with Spider - Man's quippy and more light - hearted style. Also, Two - Face. His duality could create some interesting moral dilemmas for Spider - Man. And of course, Poison Ivy. Her plant - based powers could make for some unique battles within the asylum's walls.
The Green Goblin is very memorable. His maniacal laughter and his crazy stunts on the glider, along with his complex relationship with Spider - Man, make him stand out. He was one of the first major villains and set a high bar for the others.
Another potential villain could be an ancient Wakandan enemy that was once thought to be defeated. But with Spider - Man now in the role of king, they see it as an opportunity to strike. This enemy might have some dark magic or long - forgotten technology that they use against Wakanda. Spider - Man would have to quickly learn about this enemy's history and weaknesses in order to protect his new kingdom.
Venom is quite popular in Spider - Man fanfiction. His complex relationship with Spider - Man can be explored in many ways. He can be a villain, an anti - hero, or even an ally in some really creative fanfictions. Another popular one is Gwen Stacy. Fans love to write about her and Peter's relationship, especially in alternate timelines.
There could be a genetic engineer gone bad. This villain creates dangerous hybrid creatures and releases them in the city, forcing Spider - Man 2099 to fight these unpredictable beasts. He might also have to figure out how to reverse the genetic mutations.
Doctor Octopus is another great option. His mechanical tentacles and his high - level intellect pose a significant threat. You could write a story where he creates a new, more powerful set of tentacles that Spider - Man has to figure out how to defeat.
Well, the Kingpin could be a main villain. He could see Naruto as a threat to his criminal empire in New York. He might hire some ninja mercenaries from the Naruto universe to take him down. And then there's Electro, who could be enhanced by some sort of chakra - based technology. He could use his new powers to cause chaos in the city and target Naruto specifically, thinking that he's the key to getting even more power.