Fanfiction.net might also be a good place. There are many works related to different fandoms there. However, the search function might not be as refined as AO3. You may need to dig a bit deeper by looking through different categories related to the Harry Potter fandom, as Remus and Tonks are from that series. Usually, the romance or relationship categories could be a good start.
Another option is Wattpad. Some authors post their fanfictions there. Although it has a wide range of content, not all of it is strictly focused on fanfiction. But if you search specifically for Remus and Tonks love stories, you might be able to find some interesting reads. Just be aware that the quality can vary more compared to the other two platforms.
A practical answer is Chapter 132, because it turns the idea into a concrete scene. The chapter opens with The new girl in the live-streaming room went crazy., adds pressure through Stay away from my fragrant and fresh Brother Daniu!] [Not only has the..., and ends on He stir-fried the other.
A practical answer is Chapter 130, because it turns the idea into a concrete scene. The chapter opens with This task, the first one, should have been his in the bag., adds pressure through Not to mention Wen Jiaojiao, who was still lying in the hospital on an IV..., and ends on Normally, the best.
If you want the clearest chapter reference, go to Chapter 99. Early on, Seeing the man approach, one of the individuals with a long scar across...; later, the chapter leans on How is it, have those people outside left?" "They're gone." The man spat....
The best chapter pointer here is Chapter 118, "Director Sun, When Did You Get a Barrage Above Your Head?". It opens with At 8 in the morning, several guests appeared on time next to the... and closes on Hearing this, both Jiang Yan and Shu Yan started to complain as well..
The best chapter pointer here is Chapter 100, "Ominous, there might be a bloody disaster!". It opens with The barrage was about to die of laughter. and closes on Her eyes flickered slightly as she grabbed the hand..
The best chapter pointer here is Chapter 118, "Director Sun, When Did You Get a Barrage Above Your Head?". It opens with At 8 in the morning, several guests appeared on time next to the... and closes on Hearing this, both Jiang Yan and Shu Yan started to complain as well..
If you want the clearest chapter reference, go to Chapter 137. Early on, Jiang Li personally went to Lai Fu's tomb and performed a small ritual.; later, the chapter leans on After it was finished, she took out talisman paper and gently waved it....
If you want the clearest chapter reference, go to Chapter 115. Early on, Jiang Yan was woken by a loud crowing noise.; later, the chapter leans on Annoyed, he opened his eyes and saw that the hen, which should have been....
The best chapter pointer here is Chapter 98, "Jiang Li is So Daring!". It opens with Jiang Li listened to the end and didn't have much of a reaction, only... and closes on That's why she's not scared.]] Everyone held their breath, clearly, the....
A practical answer is Chapter 66, because it turns the idea into a concrete scene. The chapter opens with I can't take it anymore, why did the young master even find a pair of..., adds pressure through If adults can't sort out their own breakfast, what good are they?, and ends on Unable to find a.