One idea could be that the Glitchtale characters are transported to the Avengers' universe. Sans could use his shortcuts to surprise the Avengers, and Betty could be a powerful villain they have to face together. Maybe Papyrus befriends Thor because of their similar jovial natures.
I think Sans and Iron Man could be great allies. Sans is intelligent in his own way in Glitchtale, with his knowledge of timelines and shortcuts. Iron Man is a tech genius. They could combine their knowledge to create strategies against common enemies. Iron Man might be intrigued by Sans' magic - like abilities and try to find a scientific explanation for them. Sans, on the other hand, would be impressed by Iron Man's high - tech gadgets.
One possible plot could be that the characters from Glitchtale end up in the world of Percy Jackson. Maybe Betty, from Glitchtale, could be mistaken for a new type of monster by the demigods. The demigods then have to figure out whether she's a threat or not. And at the same time, the Glitchtale characters are trying to find a way back to their own world.
Ink!Sans is a popular pick. His creative and somewhat unpredictable nature can bring a lot of color (literally and figuratively) to a Glitchtale crossover. He could use his paint powers in the Glitchtale world in ways that no one expects. Also, Bete Noire from Glitchtale is a character that many fans like to include. Her relationship with other characters, especially her sister, can be explored in new and interesting ways when in a crossover situation.
One idea could be a crossover with Undertale. The characters from Glitchtale could interact with the original Undertale characters in a new and unexpected way. For example, Betty from Glitchtale could team up with Chara from Undertale for some sort of dark plan. Another plot could involve a crossover with a different game like Minecraft. The Glitchtale characters could find themselves in a blocky world, having to adapt to new rules and enemies. Maybe Sans from Glitchtale could use his powers in the Minecraft world in a really creative way.
Well, it could be about the characters from Glitchtale suddenly finding themselves in the X - Men universe. Maybe Frisk would be mistaken for a new mutant with their unique abilities. They'd have to learn to fit in with the X - Men while also trying to find a way back home. The X - Men, on the other hand, would be intrigued by the strange new arrivals and their different kind of magic - like powers.
I think Percy and Sans would be really interesting. Percy has his water powers and combat skills, while Sans has his teleportation and bone - attacking abilities. Their personalities are also quite different. Percy is more of a heroic, go - get - it type, while Sans is laid - back but extremely powerful. It would be cool to see how they interact and how they could fight together against a common enemy.
Papyrus and Beast would also make for a great pairing. Papyrus is full of enthusiasm and always wants to do the right thing in Glitchtale. Beast is highly intelligent and has his own moral code. Papyrus could learn a lot from Beast's knowledge, and Beast could be inspired by Papyrus' unwavering optimism. They could work together on scientific projects in the X - Men's labs, with Papyrus bringing his unique perspective and Beast his scientific expertise.
One idea could be that Godzilla is drawn to the energy source of one of the Avengers' tech, like Stark's Arc Reactor. This causes chaos as Godzilla approaches the city where the Avengers are based. The Avengers initially see Godzilla as a threat and try to fight it. But then they realize that an even bigger alien force is using Godzilla's presence as a distraction. So, they have to find a way to communicate with Godzilla and work together to defeat the common enemy.
One idea could be that Nightwing is transported to the Avengers' universe through some sort of interdimensional rift. He then has to team up with the Avengers to fight a common enemy, like Thanos who has somehow acquired some of Batman's tech. Nightwing's acrobatic skills and detective abilities would be a great addition to the Avengers' power set.