Survival and hope are also prevalent themes. Since the original Attack on Titan story is quite dark, in alternate endings, fans often write about how the characters find hope in the most desperate situations and strive for survival in different ways. For instance, they might find new methods to deal with the Titans or new ways to build a future for humanity that doesn't involve constant bloodshed.
Well, start by imagining different possible outcomes based on the story's setup and characters. Let your creativity flow and don't be afraid to think outside the box.
An alternate ending could be that the Huntsman sacrifices himself to save Snow White. He could step in front of a fatal blow meant for her, and in his dying moments, Snow White realizes just how much he means to her. This would be a tragic yet powerful ending, showing the depth of their connection.
One alternate ending could be in 'Snow White'. Instead of the prince waking her with a kiss, Snow White wakes up on her own after a dream of her mother. She realizes she has the strength within herself and doesn't need a prince to save her.
One alternate ending could be that the main character decides to give up their quest and live a simple life instead. This could completely change the tone of the story.
There could also be an alternate ending where the Titans are revealed to be part of a much larger, more complex experiment by an ancient civilization. The characters in AOT then have to work with the outside world to not only stop the Titans but also to deal with the implications of this discovery. This ending usually involves a lot of world - building and exploration of the lore behind the Titans, and it can be quite interesting as it gives a whole new perspective on the story.
One possible alternate ending could be that Twilight Sparkle uses her magic in a completely unexpected way to stop the wedding chaos and actually uncovers a plot that was much deeper than anyone thought, leading to a celebration of friendship rather than a wedding.
Perhaps an ending where Bowser's inside world and the outside world merge in a positive way. The characters from both realms learn to co - exist and build a new, harmonious land together. For example, Mario and his friends could team up with Bowser's minions to create a utopia. The toads could teach the minions about gardening and building, while the minions could share their knowledge of the more dangerous areas of the kingdom with the toads.