One interesting idea could be an original character (oc) using the Infinity Stones in unexpected ways. For example, an oc might use the Time Stone to reverse a great tragedy in their world. Another could be an oc having a unique connection to the Stones, like being able to sense their power from a great distance.
Another interesting concept is an oc who is not a skater initially but gets drawn into the world of 'S' because of a personal connection. Maybe they are a photographer who wants to document the amazing skating feats at 'S', and through that, they end up learning to skate themselves and becoming part of the community. They could face challenges like not being accepted at first due to not being a 'true skater', but gradually earn respect.
Another way an oc can interact with the Infinity Stones is by using their own unique abilities or skills to harness the Stones' power. For instance, if an oc has the ability to manipulate energy, they could use that to better control the power of the Infinity Stones. They might also be able to create devices or spells that enhance their connection to the Stones, allowing them to use the Stones' power more effectively in different situations.
One idea could be creating an OC (original character) who is a powerful mage from a hidden dimension. They could have unique powers that disrupt Thanos' plans in unexpected ways. For example, their magic could nullify the power of the Infinity Stones temporarily.
One idea could be to create an OC with the power to manipulate stone in unique ways. For example, they can turn themselves into a stone-like form for protection or use stone projectiles in combat. Another idea is to have the OC be a part of an ancient civilization that had a connection to the stones and now they join the Justice League to protect the modern world from threats related to those stones.
One idea could be to have the Infinity Armor cross over with a superhero universe. The wearer of the armor could team up with popular superheroes to fight a common enemy. Maybe they battle an interdimensional threat that only their combined powers can defeat.
One plot idea could be a character from RWBY getting their hands on the Infinity Gauntlet and having to deal with the power corrupting them. For example, Ruby might struggle with the new - found power and how it changes her perception of right and wrong.
A really interesting plot could be based on the idea of time travel within the context of 'The Avengers Infinity Wars' fanfiction. What if the Avengers found a way to go back in time and change certain events that led to Thanos getting the Infinity Stones? They could try to prevent the destruction of Xandar where the Power Stone was first retrieved, or stop Loki from stealing the Tesseract on Earth, which was a crucial step in Thanos' plan.
One idea could be exploring what if a minor character from the movie got the Infinity Stones instead. For example, a random Asgardian warrior. They might use the power in a completely different way, perhaps trying to restore Asgard rather than the more universal aims Thanos had.
One idea could be to have the cartoon versions of the heroes and villains swap powers. For example, Iron Man could end up with Thor's lightning powers and Loki could have access to Captain America's super - soldier strength. This would lead to really unique battles and character development as they struggle to control new abilities.
One idea could be exploring the family dynamics within the Avengers during the Infinity War. For example, how do the different characters who have a sort of family bond, like Tony Stark and Peter Parker, deal with the chaos of the war? Another could be a fanfiction where a superfamily from a different dimension arrives to help in the Infinity War and how they interact with the existing heroes.