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.
An interesting approach for a Justice League Stone OC fanfic could be to make the OC a stone elemental. They are born from the essence of the stones. Their origin story could involve a cataclysmic event in the past that created them. As part of the Justice League, they can use their stone powers to create barriers, terraform landscapes during battles, and even communicate with the earth itself to sense incoming threats.
One idea could be an OC with the power to manipulate time joining the Justice League. They could accidentally create a time rift during a battle, and the League has to fix it while also dealing with the OC's insecurities about their powers.
One idea could be exploring the backstories of the lesser - known members in more detail. For example, Martian Manhunter's life on Mars before coming to Earth.
One idea could be an OC God who has the power to manipulate time. This God could be a new threat to the Justice League as they struggle to understand and combat this power. For example, the God could reverse important events in the League's history, causing chaos.
One idea could be an OC with the power to manipulate time joining the Justice League. They could accidentally create alternate timelines while trying to stop a villain, and the Justice League has to fix it. For example, the OC might go back in time to prevent a major disaster but end up changing the course of events in a way that makes the villain even more powerful in the new timeline.
One idea could be an Immortal OC who has ancient knowledge and uses it to help the Justice League prevent a threat that was foretold in a long - lost prophecy. For example, this OC might know of a hidden weakness in an upcoming powerful villain.
Maybe the OC Kryptonian has a power that is malfunctioning. They struggle to control it and it causes problems within the Justice League at first. But through the help of other members like Superman, they learn to master it. This could lead to a story of self - discovery and friendship within the team. They could face a villain who specifically targets their power, making it a race against time to get it under control.
One idea could be an OC who is a long - lost relative of Aquaman. They could have unique powers related to water control but in a different way than Aquaman. For example, the OC can turn water into different shapes and use them as weapons. Another plot could involve the OC being from a hidden underwater tribe that has a different view on Atlantis's rule. The OC could try to bridge the gap between their tribe and Atlantis while also joining the Justice League to fight common threats.
One idea could be an oc who is an old god's descendant and tries to join the Justice League. They might have unique powers that both amaze and worry the League members.
One idea could be that the OC has a unique power that the Justice League initially distrusts but later comes to rely on. For example, the OC can manipulate time in small bursts, which at first seems dangerous but is actually crucial in stopping a villain who can freeze time.
One idea could be that the Young Justice team has to prove themselves to the Justice League during a major alien invasion. The League initially doubts their abilities but as the battle progresses, they see the unique skills and teamwork of the young heroes.