One popular theme could be alternate relationships. Writers might explore relationships that didn't happen in the original story, like different pairings among the characters.
Another theme could be power - related. Maybe in the lemon fanfiction, a character's power is used in a new and interesting way in the context of a romantic or emotional situation. For example, a character's acceleration ability could be related to their feelings for another character.
A third theme could be adventure - based. The characters could go on new adventures in the 'Accel World' while also dealing with their relationships. So, it combines the action - adventure aspect of the original 'Accel World' with the romantic or emotional elements of the lemon fanfiction.
The best chapter pointer here is Chapter 266, "He Really Deserves to Die!". It opens with Upon hearing this, the deputy director's expression also turned serious. and closes on Now I see why Jiang Li despises her brother so much, utterly unreliable!"....
Chapter 264 is the strongest chapter-level answer because it starts from Jiang Li first reassured her mother, then opened the chat box with Shen... and follows through on [Do your faces hurt, you rumormongers?.
Look to Chapter 276 for the clearest answer. It begins with After listening to Jiang Li's words, Shen Lan's brow furrowed again., keeps building through Jiang Li, I think I might know who this person is., and lands on Don't overthink it and get some rest." Jiang Li nodded..
Chapter 227 is the strongest chapter-level answer because it starts from Your Four Pillars of Destiny is very strong, with wealth, authority, and... and follows through on Your three palaces are prosperous, and correspondingly, your marriage....
A practical answer is Chapter 269, because it turns the idea into a concrete scene. The chapter opens with The next morning, Shen Lan's personal account posted a Weibo., adds pressure through Too excited to remember to switch to his alternate account, he..., and ends on At that time, people.
If you want the clearest chapter reference, go to Chapter 227. Early on, Your Four Pillars of Destiny is very strong, with wealth, authority, and...; later, the chapter leans on The comments section was filled with amazement as well..
A practical answer is Chapter 271, because it turns the idea into a concrete scene. The chapter opens with He had barely finished speaking when he received a withering look from..., adds pressure through Forget about your brother;
A practical answer is Chapter 250, because it turns the idea into a concrete scene. The chapter opens with The knowledge that several guests were soon returning had fans arriving at..., adds pressure through Not seeing me for so many days and not even asking how I am, you think—"..., and ends on.
A practical answer is Chapter 220, because it turns the idea into a concrete scene. The chapter opens with I know everyone has many questions, and I'm here to answer them one by..., adds pressure through Carrying the heat surge of his research topics, he instantly shot to..., and ends on However.
Look to Chapter 243 for the clearest answer. It begins with Hahaha, the young master's face has gone white, but I got a scare just now..., keeps building through Who knocks on the door in the middle of the night, especially in a place..., and lands on Perhaps feeling that the atmosphere had become.