I'm not sure about specific fanfics with exactly those three in this context. However, you can try searching on popular fanfic platforms like Archive of Our Own. Just be sure to check the tags and ratings to find the ones that suit your taste.
There are many Overwatch fanfics out there, but finding ones with Tracer, D.Va and Futa might be a bit tricky. You could join Overwatch fan communities on social media platforms like Reddit or Discord. There, fans often share and discuss their favorite fanfics, and you might be able to find what you're looking for through their recommendations.
Searching for fanfics with such specific combinations can be difficult. You can start by looking at general Overwatch fanfic categories on websites. When you find a fanfic that has Tracer or D.Va in it, check the character tags within the fanfic description to see if there are any related or crossover elements that might include what you want. Also, some fanfic writers may take requests, so you could try reaching out to them in a respectful way to see if they would be interested in creating something with those characters.
Chapter 253, "She Hit My Head Three Times, I Hit Hers Seven Times", is the clearest early answer because it turns Round Brain's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Wen Jiaojiao immediately lost her composure, leaping up from the bed...
Chapter 613, "When a Whale Falls, All Life Thrives", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Hearing He Wen's words, Shen Lan was so excited she nearly sprayed...
Chapter 346, "This person doesn't seem to like her very much", is the clearest early answer because it turns Director Zhang's situation into a concrete plot event. The chapter gives readers a real answer by opening on Yes," Jiang Li said, "I learned that this 'Night Walk' is an...
Chapter 358, "That dress of hers must be a fake!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, I just drove here slowly." In an instant, all cameras swiveled in his....
Chapter 306, "I Believe Whatever Miss Jiang Says!", is the clearest early answer because it turns Aunt Zhou's situation into a concrete plot event. A useful checkpoint is the way the scene starts with But Jiang Li seriously shook her head, "No, Aunt Zhou, this matter...
Chapter 447, "Going Viral on the Internet", is the clearest early answer because it turns Zheng Xun's situation into a concrete plot event. It opens with Old Sir Jiang: "...." His face had grown even worse. and closes on She quickly grabbed He Wen's laptop and indeed saw that the various....
Chapter 324, "Enrollment", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. The chapter gives readers a real answer by opening on An ancient and majestic building, striped red and white, gathered the...
Chapter 615, "River·Doraemon·Li", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. The chapter gives readers a real answer by opening on Everyone huddled close with their bowls in hand. and ending on This wind turbine is what I exchanged for yesterday..
Chapter 689, "Is the Soundproofing of This Private Room So Good?", is the clearest early answer because it turns Shang Shaobai's situation into a concrete plot event. Early on, Jiang Li found the restaurant Shang Shaobai had mentioned, and had Ji....
Chapter 482, "Someone Might Need Me", is the clearest early answer because it turns Pei Ye's situation into a concrete plot event. The chapter gives readers a real answer by opening on Other people caught a glimpse of Zhao Lang's cold and stern face and...