I think Freddy from FNAF would be really interesting. He's the leader among the animatronics, and seeing him interact with the dinosaurs would be cool. He could use his calm and somewhat authoritative presence to make friends with the more intelligent dinosaurs.
Littlefoot from The Land Before Time could be a very interesting character in this fanfiction. He's curious and brave. When he meets the animatronics, he might be the first to approach them and try to understand what they are. His friendly nature could help bridge the gap between the two very different groups.
In such a fanfiction, there could be really strange and exciting scenarios. Maybe the animatronics from FNAF end up in the prehistoric world of The Land Before Time. They might interact with the dinosaurs in ways that are both comical and a bit spooky.
Naruto would be really interesting. His never - give - up attitude would make him stand out in the spooky FNAF world. He'd probably be the one to charge headfirst into danger, whether it's facing the creepy animatronics or trying to solve the mysteries of the place. He could also try to befriend the animatronics if he thought they were being controlled against their will, just like he did with some of his enemies in the Naruto world.
Frisk could be a very interesting character to focus on. Frisk has the power of determination, which could be used in unique ways in the FNAF setting. They could befriend some of the animatronics, using their kindness and determination. Also, since Frisk is the player - controlled character in Undertale, it would be interesting to see how they adapt to the more dangerous and unpredictable world of FNAF.
Aphmau from MyStreet and Freddy Fazbear would be an interesting combination. Aphmau is a strong - willed leader in her world, and seeing her face off against Freddy, the iconic animatronic from FNAF, would be exciting. Another interesting pair could be Aaron from MyStreet and Foxy. Aaron is often protective, and Foxy has that unpredictable nature.
I think Freddy Fazbear and Toriel would make an interesting pairing. Freddy is this big, imposing animatronic, while Toriel is a motherly figure. Their interactions could be really cool, like Toriel trying to understand what Freddy is and Freddy being a bit confused by Toriel's kindness.
Frisk and Chica would also be a cool combination. Frisk is all about kindness and determination, and Chica is this animatronic with a bit of a goofy side. Frisk could try to understand Chica's motives and maybe even help her find a new purpose other than scaring people at night.
I think Dolohov could be the most interesting. He's a Death Eater, so he has a dark and mysterious side. Meeting Hermione could be a turning point for him. His interactions with her might make him question his loyalty to Voldemort. It would be fascinating to see his internal struggle as he deals with Hermione's goodness and intelligence.
It would probably be the Shinigami. Since it's a mysterious and powerful being from another realm, its motives and actions would be really interesting to follow.
It could be Ace. Since Ace was part of Whitebeard's crew and also Luffy's brother. His role in this meeting could be very crucial. He would be like a bridge between the two different worlds of Luffy and Whitebeard. His loyalty to Whitebeard and his love for Luffy would add a lot of emotional and interesting elements to the story.
I think Sonic himself would be the most interesting. He's so different from the Pokemon world. His super speed and his attitude would really stand out. He doesn't have the typical powers of a Pokemon, like shooting fire or electricity. His way of dealing with problems, which is mostly running really fast and spinning into things, would be really unique in the Pokemon world.