Well, one place to look for such fanfiction could be FanFiction.net. There are often many Sonic - related fanfics there. Maybe search for 'Tails turns into a robot' directly in the search bar on the site. Another option is Archive of Our Own (AO3). It has a large collection of fan works as well, and you might find some interesting takes on Tails becoming a robot in the Sonic universe.
To find 'Tails Turns into a Robot' fanfiction, start with general fanfiction search engines. Some fanfiction writers also promote their works on Tumblr. You could search for relevant tags like #Tails #Robot #SonicFanfiction. Also, keep in mind that the quality of fanfiction can vary widely. Read the reviews or summaries first to get an idea if it's the kind of story you'll enjoy, especially when it comes to this specific and interesting concept of Tails transforming into a robot.
In a 'Tails Turns into a Robot' fanfiction, it could be that an ancient technology is accidentally activated by Tails. This technology fuses with him and turns him into a robot. He then discovers that he has a special connection to an ancient robotic civilization. He has to navigate his new identity, learn about this civilization, and decide whether to embrace his robotic self or try to find a way back to his normal form all while facing challenges from those who fear or want to use his new - found powers.
One popular 'Tails turns into a werefox' fanfiction might be 'The Werefox Tails' Adventure'. It often has Tails dealing with his new werefox form in a world that doesn't fully understand it. He has to learn to control his new powers and instincts while also facing some challenges from those who fear the unknown. Another one could be 'Tails: The Werefox Origins' which delves deeper into how he actually turns into a werefox, perhaps due to some ancient magic or a scientific experiment gone wrong.
One interesting Robot Tails fanfiction could be about Tails building a super - advanced robot version of himself to help Sonic in a particularly tough battle. In this story, the robot Tails has unique abilities like flight speed faster than the original Tails and advanced weaponry built into his tails.
One good 'tails vs tails doll fanfiction' story could be 'The Clash of Tails'. In this, Tails is depicted as a brave hero facing off against the rather eerie Tails Doll. It shows their different powers and how Tails uses his intelligence to try and outwit the doll. Another might be 'Tails' Duel with the Doll' which focuses more on the action-packed combat between them.
One popular 'tails x tails doll fanfiction' might be 'The Adventures of Tails and Tails Doll'. It often features unique adventures where the two characters interact in unexpected ways. Another could be 'Tails and Tails Doll: A New Bond' which focuses on them forming a special connection. There's also 'Tails Meets Tails Doll in a Mysterious World' that takes place in a strange and magical setting.
There might be a fanfiction where Tails is an outcast in his community for some misunderstood reason. He endures loneliness and sadness as he tries to prove his worth. This type of story can really tug at the heartstrings as we see Tails face so much adversity all by himself.
Sonic turning into a robot in fanfiction could also be a self - sacrifice situation. Suppose there's a powerful energy source about to explode and Sonic, in order to contain it, fuses with some nearby robotic parts. This would give him the ability to withstand the blast but at the cost of his normal form. His friends would be shocked at first but then try to find a way to restore Sonic. It could lead to an interesting adventure filled with emotions and high - stakes situations.
One possible plot could be that Tails is exposed to some dark energy or a powerful, corrupting artifact. This makes him gradually turn against his friends. He might start using his intelligence to outwit Sonic and the others for his new, evil goals.
Sorry, I'm not aware of specific 'cosmo and tails collar fanfiction' stories directly. You could try searching on fanfiction platforms like Archive of Our Own or FanFiction.net.
Another interesting one is 'Wave and Tails in the Mysterious Realm'. In this story, they accidentally enter a strange realm full of magic and unknown creatures. They have to use their wits and skills to find a way back home. The description of the realm is very vivid, making it seem like a real place.