A boy from District 9 who is a genius at strategizing. He might have studied the previous Hunger Games extensively and uses this knowledge to form alliances and plan his every move. He could be a complex character, torn between his own survival and his moral compass.
There could also be a Capitol citizen who becomes disillusioned with the Hunger Games. He decides to secretly help a tribute in the 63rd Hunger Games. This character could add an interesting dynamic as he tries to navigate the strict rules of the Capitol while trying to do what he believes is right.
There could be a disabled tribute from an unknown district. Despite his physical limitations, he has a brilliant mind and uses his strategic skills to form alliances and stay alive in the 73rd Hunger Games.
I'm not sure specifically as I haven't read this fanfic. But it could be new tributes created by the fanfic author.
There could be an older tribute from District 9. He has seen many harvests and is very wise. He might use his knowledge of grains and farming to his advantage in the arena, like knowing which plants are edible. And don't forget about the tribute from District 2 who is a trained fighter. He's very strong and confident, but also has a soft side that he tries to hide during the games.
A nerdy student who has been underestimated all his life could be a main character. He uses his intelligence to outwit the more physically strong opponents. For example, he could create traps using his engineering knowledge.
There could be a Capitol - trained healer who is sent into the Hunger Games as a form of punishment. He has knowledge about the blight and its effects, which could be both an advantage and a disadvantage in the arena. His main goal becomes survival rather than following the Capitol's cruel rules.
Perhaps an older tribute from a previously overlooked district. He has been observing the Hunger Games for years and has a secret plan. He has a lot of knowledge about the Capitol's tactics and uses this to outwit the Gamemakers and survive in the 100th Hunger Games.
A new character could be the main one. Maybe a girl from a fishing district who has excellent swimming and diving skills. She could be a tough competitor, knowing how to navigate the beach and the sea better than others. Or it could be a boy who was exiled to the beach before the Games started and has learned all the secrets of the beach, like where the fresh water sources are and the safest places to hide from other tributes.
A street - smart orphan from the slums of Coruscant could be a main character. They would have grown up tough and know how to fend for themselves. Another could be a Capitol - bred citizen who volunteers for the Games out of a sense of adventure or to prove something. Maybe they think they can handle it because of their privileged upbringing but soon realize it's not as easy as they thought.
One main character could be a young girl from District 9, who is really intelligent and uses her wits to survive. She might form an alliance with a boy from District 12, who is known for his speed and agility. They make an unlikely duo but their combined skills help them in the games. There could also be an older tribute from District 7, who has a lot of experience in the forests and uses that to his advantage in the arena.
A girl from District 11 who is an expert at climbing trees and has a strong sense of justice. She could be one of the main characters, using her skills to survive in the arena and also standing up for the weaker tributes.