Natsharon

NatSharon is the femslash ship between Natasha Romanoff and Sharon Carter from the Marvel and Marvel Cinematic Universe fandom.

Earth 616
Natasha Romanoff and Sharon Carter are two agents of S.H.I.E.L.D, they met and became friends after Steve Rogers' death, Natasha helped Sharon against Dr Faustus and Red Skull. After Steve came back, Natasha and Sharon still went to some missions together as a duo; they went to a party and Sharon tried to convince Natasha that they were both going to a trap, but Nat didn't listen to her, but Sharon was right...Natasha was recognized by lady Alicia who also saw Sharon and referred her as "Natasha's mother", both Nat and Sharon got stuck in the party and Sharon asked if Alicia thinks she would be able to keep both her and Natasha remand, their mission was a success thanks to their skills and the help of Tatiana, after the mission, Natasha made jokes about Sharon "being her mother"  calling her "mom".

Sharon and Natasha went to more missions together, including a mission in Russia, Nat calls Sharon by "My friend Agent 13", they really know how to work together as a duo gathering their skills and lending their weapons to each other, they are not just good agents but good friends as well, they care about each other and trust each other.

Fanon
Black Widow and Agent 13 is a beloved friendship to comic fans, the way they work as a duo as as friends is interesting and cool, their dynamics worked very well and it is one of the greatest friendships between two female agents in Marvel comics fandom. On AO3, Natsharon is the second most written ship for Sharon. There are currently 360+ written works.

Fandom

 * FAN FICTION

Trivia

 * Both have been in relationships with men who took on the mantle of Captain America.