Ruby and Frisk would be a really interesting pairing. Ruby is full of energy and determination, and Frisk has that unwavering kindness. They could learn a lot from each other, especially in terms of how they approach difficult situations and make decisions.
Blake and Toriel could be a great match. Toriel is a motherly figure, and Blake, with her own complex past, could benefit from Toriel's wisdom and care. They could also bond over their love for books and stories, and Toriel might give Blake some new perspectives on her own journey.
Yang and Undyne would be a powerful combination. Yang is all about strength and a bit of a hot - head, while Undyne is a fierce warrior. They could have some epic battles together, but also learn about different kinds of strength. Yang could teach Undyne about the concept of Aura, and Undyne could show Yang some of her more unique combat techniques.
I think Leonardo and Papyrus would make an interesting pairing. Leonardo's leadership and discipline could contrast with Papyrus' more naive and enthusiastic nature. They could learn from each other, like Leonardo teaching Papyrus some ninja moves, and Papyrus showing Leonardo how to have more fun. Another great pairing could be Donatello and Alphys. They are both the 'tech - smart' characters in their respective universes. They could collaborate on some crazy inventions that combine Undertale technology and Turtle - made gadgets.
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.
Grunkle Stan and Toriel could be an interesting pairing. Grunkle Stan is a bit of a con artist but has a good heart deep down. Toriel is a motherly figure. They could have some great interactions where Toriel tries to get Stan to be more honest and kind, while Stan might try to find some business opportunities in the Undertale world. It would be a clash of personalities but also a chance for growth for both characters.
Another interesting pairing would be Ron and Papyrus. Ron is known for his loyalty and his love for food, and Papyrus is this enthusiastic skeleton who loves cooking and making friends. They could bond over food, with Ron introducing Papyrus to some wizarding world delicacies like Butterbeer and Pumpkin Pasties, and Papyrus showing Ron his 'Spaghetti Surprise'. Their friendship could also be a source of comic relief in a more serious crossover story.
Frisk and Dave Strider would be an interesting pairing. Frisk is all about kindness and determination in Undertale, while Dave is this cool, sarcastic guy from Homestuck. Their different personalities could lead to some really fun interactions, like Dave trying to be all cool while Frisk just goes about their business of being kind to everyone.
Ruby and Cayde - 6 would be an interesting pairing. Ruby is young and full of energy, always eager to learn and fight. Cayde - 6 is a witty and experienced Guardian. Their interactions could be really fun, with Cayde - 6 teaching Ruby some of his trick - shooting skills and Ruby showing Cayde - 6 the beauty of her Crescent Rose. Another great pairing would be Weiss and Ikora Rey. Weiss is a highly - trained fighter with a strong sense of discipline, and Ikora Rey is a powerful Warlock with great knowledge. They could share their knowledge of magic - like abilities, Weiss with her Glyphs and Ikora with her Light - based spells. Yang and Zavala could also be an interesting pair. Yang is all about brute strength and a go - getter attitude, while Zavala is a respected leader. Yang could learn about leadership from Zavala while Zavala could admire Yang's tenacity.
Ruby and a Skaven Assassin could be an interesting pairing. Ruby with her speed and scythe skills would be pitted against the sneaky and devious Skaven. It would be a battle of wits and speed. Another great pairing could be Weiss and a High Elf Mage. Weiss's elegance and ice powers could contrast and interact with the Elf's magic. And Yang and a Chaos Space Marine. Yang's brute strength and brawler style against the super - powered and corrupted Chaos Space Marine would make for an intense fight.
The Doom Slayer and Ruby would be an interesting pairing. Ruby is young and full of energy and hope, while the Doom Slayer is a silent, stoic force of destruction against evil. Their interactions could be really cool, like Ruby trying to understand the Doom Slayer's lack of words but seeing his determination and being inspired by it. And the Doom Slayer might see Ruby's potential and unwavering spirit in the face of danger as something similar to his own.
Ben and Ruby would be an interesting pairing. Ruby is young and full of energy, always eager to learn and improve. Ben, with his experience using the Omnitrix, could teach her a lot about adapting to different situations. And Ruby could show Ben the importance of teamwork in her own unique way.
Yang and Kenpachi would be a wild and exciting pairing. Yang is all about brute strength and has a bit of a hot - headed nature. Kenpachi is the same, always looking for a good fight. They could have some epic battles together, or team up and be an unstoppable force. Also, Blake and Urahara could be an interesting pair. Blake is stealthy and intelligent, and Urahara is a mastermind with all kinds of tricks up his sleeve. They could scheme together to solve the problems that come up in the crossover world.