Late game team fighting, supports and top laners

Hello everyone reading this. I'm having some trouble getting my win rate up in ranked. My goal this season is at least G5. I'm a support main in Bronze 2 just looking for a way to do better in games. I feel my most notable problem is that I am not contributing enough late game to secure my team's win. Are there any support, or Top lane champions that work well in team fighting situations late game. Please if anybody can offer any advice that would be great thank you!