Hulk is another character that could be popular. His brute strength and his unique relationship with Thor in Ragnarok are great fodder for fanfiction. Writers might explore his time on Sakaar in more detail, or his interactions with the Asgardians when he finally arrives in Asgard.
One interesting plot idea could be the exploration of Asgardian characters' reactions to Thor's journey in Ragnarok from a different perspective. For example, how the common Asgardians felt about Thor's battles and his newfound friends. Maybe some of them were skeptical at first but then became inspired by his growth.
Brunhilde is a key figure in fanfiction as well. She is the one who selects the human fighters. Writers might explore her backstory, her reasons for choosing certain humans, and her own internal struggles. Her complex relationship with the gods and her determination to give humanity a chance make her an interesting character to write about.
One popular Asgard Watches fanfiction might be those that explore the unique designs of the watches in a fantasy - adventure setting. For example, a story where the watch has magical powers and the protagonist uses it to journey through different realms.
Yumi is often a popular character in the fanfiction. Her kind and somewhat reserved nature makes her a great character to build stories around. Writers can explore her inner thoughts and feelings more deeply in fanfiction.
In the Thor Ragnarok original story, Thor is obviously a main character. He's the son of Odin and has the power of thunder. Loki, his adopted brother, is also important. He's full of tricks. Hela, the goddess of death, is a major antagonist. She wants to rule Asgard. And Valkyrie, she's a former Valkyrie who joins Thor in his fight. There are also other characters like Odin, though his role is more in the setup of the story.
The main characters are Thor, of course. Also, Hulk, Valkyrie, and Hela. Thor is the central figure trying to stop Ragnarok. Hulk is his friend and also an opponent for a while. Valkyrie is a strong female character who helps Thor. And Hela is the main villain causing all the chaos.
One character that could be added is the Enchantress. She could use her magic to either help or hinder Thor's time - travel attempts. Another could be Beta Ray Bill. He could team up with Thor in the different time periods they visit during their time - travel adventures. And perhaps the Warriors Three could be brought back through time - travel shenanigans, even if they died in the original Ragnarok storyline.
You can start by looking on fanfiction websites like Archive of Our Own or FanFiction.net. These platforms usually have a wide range of fan - created works, including those related to Asgard Watches.
Ben himself is obviously very popular. After all, it's his Omnitrix that's the centerpiece. Then there's Four Arms, who is often included because of his brute strength. Vilgax is also a common one as he is a major villain in the Ben 10 series and makes for a great antagonist in the Death Battle scenarios.
Uma is a very popular character in fanfiction related to Auradon Watches Descendants 2. She has a strong personality and her own motives. She is a rival to Mal, which makes for some great storylines in fanfiction. Fans love to write about her attempts to gain power and her relationship with the other characters. Harry Hook is also a favorite. His wild and unpredictable nature, along with his loyalty to Uma, are aspects that fanfiction writers like to explore. His pirate - like charm adds an exciting element to the stories.