You can start by looking on Archive of Our Own (AO3). It has a large collection of fanfictions, and you can easily search for 'Mercy x Reader' ones. There are usually a lot of well - written stories there. Another place is FanFiction.net. It has been around for a long time and has a decent selection as well.
Well, Tumblr can also be a good source. Many fanfiction writers post their 'Mercy x Reader' works there. You can search relevant tags like '#Mercy x Reader Fanfiction' or '#Mercy Reader'. Also, some Overwatch - specific fanfiction communities might have great finds. These communities often have dedicated sections for different pairings, and 'Mercy x Reader' is likely to be one of them.
Chapter 327, "Beast Tide Battle, Wolf King and the Hidden Move, White Dew Gu’s Dead End (Part 5)", is the clearest early answer because the buildup finally cashes out in a real clash. Early on, Because the Iron Arrow flew above the Cold Ruins Tripod, a fierce.... By the end, The Cold Blood Blade, along with the crossbow arrow, simultaneously....
Chapter 304, "The Defeated Longyou Army, Xia Army Cannot Escape, Holy Tripod", is the clearest early answer because Long Mountain gets a payoff that changes the stakes. A useful checkpoint is the way the scene starts with The people's expressions, which were originally somewhat dispirited,... and follows through with Unstoppable Longyou Army." "Decisively defeat the Xia Army!.
Chapter 312, "Reining In, Killing, Shock and Submission (Part 2)", is the clearest early answer because the violence around Meng Ying becomes final instead of hypothetical. The chapter turns that into something concrete by moving from You overestimate those so-called high-level figures you keep talking... to The resource allocation model of the Longyou camps predestined that a....
Chapter 338, "Rapid Progress, Martial Arts Skills, Dual Advance Eastward, Dormancy Period", is the clearest early answer because the violence around Xia Hong becomes final instead of hypothetical. It opens with Lu Yang nodded, then continued speaking after sitting down: "Beining... and closes on What I found out is that besides a population of over 20,000, a....
Chapter 312, "Regaining Focus, Killing, Shock, and Submission (Part 3)", is the clearest early answer because the violence around Peng Bo becomes final instead of hypothetical. The setup is Those seem to be the families of Meng Ying, Jiang Ping, and several..., but the pressure keeps building through Weren't they supposed to switch allegiance to Great Xia?.
Chapter 39, "Is This Book an Out-of-Print Buddhist Scripture?!", is the clearest early answer because it turns Buddhist's situation into a concrete plot event. The chapter turns that into something concrete by moving from Qi Tianyu had been looking forward to watching Jiang Li's drama...
Chapter 108, "Without accumulating virtue through words, calamities of bloodshed will only increase, not decrease.", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event. Early on, In a glamorous Michelin three-star restaurant, Su Yinwan and Shang....
Chapter 191, "Sister, Jiang Cheng is bullying me!", is the clearest early answer because it turns Shen Lan's situation into a concrete plot event. A useful checkpoint is the way the scene starts with This change made Jiang Cheng extremely uncomfortable.
Chapter 31, "Master, I've been having some bad luck lately!", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event.
Chapter 304, "The Defeated Longyou Army, Xia Army Cannot Escape, Holy Tripod", is the clearest early answer because Long Mountain gets a payoff that changes the stakes. It opens with The people's expressions, which were originally somewhat dispirited,... and closes on Long Mountain originally had just over 70,000 people.. The key payoff is that the chapter closes with "Decisively defeat the Xia Army!, which gives Long Mountain a stronger narrative position and pushes the power growth onward.