I use a ton of mods, but lately I'm in love with Lumpinou's ones.
Woohoo Wellness & Pregnancy Ovehaul — adds such things as pregnancy preferences (your sim can have an unwanted pregnancy even if they're not a child hater), risky woohoo, paternity testing, realistic reactions to teen pregnancies, artificial insemination and surrogacy, and adoption overhaul.
I haven't tested everything yet – my sims are boring and have no drama in their lives lol, but I've adopted a kid through this mod. And it's so much better than what we have in game! You have to ask your partner if they agree to an adoption. Then you receive a visit from an adoption agent, who can decline your request if you don't have enough money and living space to have a child.
And if you adopt a baby or a toddler, they won't know that they were adopted and you can reveal it later. And teens can go and contact their biological parents if they want to (I think a parent gets picked up randomly, I've got a notification that my sim's bio father is Rohan Elderberry (Britechester townie).
First Impressions — adds sentiments when sims meet each other, a useful tool to decide who I want my sim to be friends with. :)
Road to Romance — adds more options to romance menu, such as “talk about life together”, “make future plans”, “enthuse about your kids”. Finally my spouses can talk about serious matters and not only flirt.