Sadly I've never collected game screenshots of my absolute favorite Sims in their early lives since I was new to the whole constantly taking pics of your Sims thing; I probably have computer screenshots somewhere but printed off my screen, not the game's camera itself. But here goes:
I would say generally my favorite Sim(s) has to be Loretta Lawrence and her (then) toddler son Daniel. Originally my earliest Sims in Sims 4 (not including my old version of my simself) and I've really come to love every bit of them as they've gone through the years. Technically I made Daniel first to try out toddlers and then his mother, but both are equally favored. I also like to think they're English.
Loretta had some wild(!) teen years and lead to the unexpected birth of young Daniel, who's never known his father. Loretta's parents were extremely bothered by this and upon the first day she grew up into YA she was left on her own. A starving artist by trade as well as a single parent, she scrounged up some funds to live in a small, spacious home in Oasis Springs. The vistas from the front porch were more than enough to start painting in, yet the money she made was still not nearly enough. She couldn't afford much for little Daniel, who seemed like an Inquisitive child and was always looking for something to do. With few options, he would always play in the toilet and sometimes wander at night out on the streets in nothing but his diaper talking to random strangers, in which Loretta quickly took him back inside, tucked him back in, and started learning to lock doors.
At the end of the day though, she truly loved her little boy and could never part ways with him, and I believe young Daniel loved his mother very much. Along the way, Loretta encountered and met a master chef constantly jogging out in her neighborhood (my old simself) who was a single gay bachelor but held deep compassion for Loretta's plight and the future she wants to secure for Daniel. So the master chef decided to take them both in to his small abode in Willow Creek and began to remodel the house to fit them both. Eternally grateful of this, Loretta was now financially secure in the funds that her new best friend had on his person. However, Daniel grew up into a child and became a bit of a devil child, seeing as how he was a naughty boy as a toddler. Loretta felt in a way that she had already failed at parenting, but strived to continue giving him all the love he needs. This prompted into Daniel's eventual development into a momma's boy.
Loretta was now finally free to pursue a career in the arts as Daniel was perfectly fine on his own now, and in the meanwhile the master chef became an elder and married his neighbor, Travis Scott, and moved in together, to which the household grew and so did their funds. Loretta's new room in the house became her little art studio, and her creative juices began flowing tremendously from her new creative space. The tiny house only grew in wealth with the little space it had, and not long after Daniel's birthday into a teen, both Travis and then the master chef died a few days later, leaving the will of their estate and finances directly to her, as a final parting gift. Now the prideful nerd that he is, Daniel has his life ahead of him, though still a momma's boy, and would never let his mother go. Loretta would never be parted from her son either, and as she now has reached middle-age, she's also become a famous artist, with an agent and everything! Life couldn't be anymore sweeter than this.
I'll try to take pictures of their current state as they are now, I'm sure you'll enjoy them, but I do already have them on the Gallery if you want to see what they look like at their start
here.