A boy from District 4 who is an expert fisherman. He's not just physically strong but also very clever. He could use his fishing skills to catch food in the arena and also use the fishing nets as weapons or to set traps for other tributes. His backstory could be that he wants to win the Games to bring pride back to his district which has been overlooked in recent years.
A girl from District 12 could be a great main character. She could be different from Katniss, maybe she's more of a strategist than a hunter. She uses her wits to form alliances and outsmart her opponents in the arena.
I'm not sure specifically as it depends on the fanfic. But it could be a new set of tributes from different districts. Maybe a strong - willed girl from District 4 and a smart boy from District 11.
A previous victor forced to return to the Games for the 50th edition could be a great main character. Their experience from the past would give them an edge, but also a lot of emotional baggage. It would be interesting to see how they handle the new challenges and younger opponents.
A young girl from District 12 who has been secretly training in combat skills her whole life. She could be the main character, using her wits and skills to survive the games.
It could be a young girl from a poor district who has been training in secret for years. She has a strong will to survive and a deep - seated desire to expose the Capitol's cruelty. Her journey through the Games could be about not just survival but also sparking a revolution among the tributes.
A girl from District 11 who is an expert at climbing trees could be a great main character. She could use her skills to hide from other tributes and also find food sources in the arena.
There could be a boy from District 4 who is an expert fisherman. He uses his knowledge of water and fishing to survive in the arena. He might form an alliance with the girl from District 12, and together they face the challenges of the 50th Hunger Games. He is also very clever and can outwit other tributes.
Survival is a very common theme. Just like in the original Hunger Games, in 50th Hunger Games fanfic, tributes have to find ways to outwit and outlast their opponents. They might have to deal with harsh environments and limited resources.
The main character could be a new tribute who has some unique skills or abilities. For instance, a tribute who is an excellent tracker but also has a kind heart. Or it could be one of the minor characters from the original 4th book who gets a chance to shine in the fanfiction, like a young Capitol citizen who starts to question the Hunger Games system after seeing the events of the 4th games.
Perhaps an older brother who volunteers to take his younger sister's place in the 50th Hunger Games. He has a strong sense of family loyalty and his journey in the Games could be about protecting the other tributes who remind him of his sister.