Well, Mirajane could be part of the harem. She has a motherly side and would want to comfort Natsu if he was betrayed. Levy is also smart and resourceful, and she could use her skills to help Natsu out. Juvia, with her obsessive love for Gray, might transfer some of that intense loyalty to Natsu if she saw him in a desperate situation after being betrayed.
Lucy could be a likely member. She has a close relationship with Natsu already in the original story. Another one could be Erza. Her strong and independent nature might be attracted to Natsu's new godlike power. And Wendy, being young and impressionable, might also be part of the harem as she looks up to Natsu.
In addition to Lucy and Erza, there could be other female characters from the series. Maybe some minor characters who have always admired Natsu from afar. For example, that one girl from the guild who always blushes when Natsu is around. Another possibility is a powerful female dragon who sees Natsu's transformation into a Dragon God as a sign of his worthiness. She might join his harem, bringing a different kind of relationship dynamic as she has her own dragon - like qualities and power. And there could be a female mage from a different guild who hears about Natsu's new status and is intrigued, eventually becoming part of his harem.
One idea could be that Natsu is betrayed by his closest friends in the guild, and in his time of despair, a group of female characters form a harem around him to help him heal and regain his confidence. For example, Lucy could be the first to reach out, using her celestial magic to show him there are still things to fight for. Another plot could involve Natsu being betrayed by a powerful dark mage who manipulates his guild against him. The harem, which might include Erza, Wendy, and others, then trains Natsu in secret to become stronger and take revenge on those who wronged him.
Well, characters like Nightcrawler could be part of it. His acrobatic and teleporting abilities would add an interesting dynamic to the harem. Another could be Iceman. His cool (pun intended) powers and his somewhat reserved personality could create an interesting relationship with Superboy. And then there's Cyclops, with his leadership skills and powerful optic blasts. He could also be a likely candidate for the harem.
Tuxedo Mask could also be in the harem. He has a long - standing relationship with Usagi, and in a harem scenario, his feelings for her could be even more intense, competing with others for her love.
Rebecca could potentially be in Luffy's harem. After Luffy helped her in Dressrosa, she might develop feelings for him. She is a strong - willed and kind - hearted character. Another could be Shirahoshi. Luffy has a special connection with her as he saved her from being captured. Her gentle and innocent nature would contrast with some of the other more assertive members of the harem.
Definitely Orihime. She is the type who would be easily attracted to Goku's pure - heartedness and his determination to protect. Her own insecurities might be soothed by Goku's confidence. Rukia, with her sense of duty, could find herself drawn to Goku's selfless acts of heroism. And Neliel could also be part of the harem. Her child - like form and yet powerful true form would create an interesting relationship with Goku, as he might be protective of her in her child form and respect her power in her true form.
An anti - hero or a morally grey character might be the antagonist. This character could have a different view on relationships and superhero life. He convinces Spider Man that the harem is holding him back from achieving greater things. And Spider Man, being influenced, betrays the harem.
Well, obviously Lucy from Fairy Tail would be a likely candidate. She already has a strong connection with Natsu in the original series. Then from the world of Bleach, Rukia could be an interesting addition. Her cool and collected nature would contrast with Natsu's hot - headedness, and her Soul Reaper powers would add an interesting dynamic to the harem. Also, from Attack on Titan, Mikasa could be in the harem. Her strong combat skills and protective nature towards Eren could translate into a similar protectiveness towards Natsu in the fanfiction.
In addition to the obvious ones like Sakura and Hinata, Ino could also be part of the 'naruto x yugito harem'. Ino has always been competitive with Sakura over Sasuke, but in this fanfiction scenario, she might see Naruto in a new light and be drawn to him. Tsunade could also be an interesting addition. She is a powerful and experienced ninja, and her relationship with Naruto as his mentor could potentially take on a different, more romantic - ish turn in the context of a harem fanfiction.