You can try looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. These platforms have a vast collection of Miraculous Ladybug fanfictions. Just use the search bar and type in relevant keywords like 'lost' to find ones that might match what you're looking for.
Master Fu would be a key figure. He could use his knowledge of the Miraculous and magic to try and restore Ladybug's memory. He might need to perform some kind of ritual or use a special potion. Meanwhile, Chat Noir would have to keep Ladybug safe from any villains who might take advantage of her vulnerable state.
The sense of mystery in an 'absolutely lost' Miraculous Ladybug fanfiction can be really captivating. When the characters are lost, it could be in a physical sense like in a strange new location, or in an emotional sense, not knowing what to do. This creates a lot of tension and makes readers eager to find out how they'll get out of that situation.
One idea could be that Ladybug loses her memory during a battle with a new villain who has the power to erase short - term memories. Chat Noir has to protect her while also trying to find a way to restore her memories. Maybe he takes her to Master Fu, who has some ancient techniques that might work.
Maybe Hawk Moth would take advantage of her lost memory. He could try to deceive her into thinking he was a friend or an ally, and then manipulate her into giving up her Miraculous. This would add a lot of drama and conflict to the story.
It could change the power dynamics. Without her memory, Ladybug might not be as effective in using her powers or leading the fight against Hawk Moth. This could lead to a shift in the balance of power in Paris.
In an akumatized Ladybug fanfiction, the akuma might enhance her powers in unexpected ways. For example, her Lucky Charm could become a more powerful and unpredictable object. Her akumatized form might also have a darker and more menacing look, perhaps with a more aggressive fighting style. Writers could explore how the heroes and villains interact with this changed Ladybug.
A new villain could have a weapon that specifically targets Ladybug's powers. When she tries to use her yo - yo or her powers of creation, it backfires and causes her harm. This would force her to rely on her wits and Chat Noir more than ever. They would need to find a way to neutralize the weapon and heal Ladybug.