I have some. They're the best for having pets because they have time for them and the pets also help to keep the social needs up. You could also give them roommates to spice things up if the house is big enough. Finding romance can be interesting since you're only focusing on that one sim.
- Alexander Harmaja is a famous self-emplyed pianist who lives on Windenburg island with his dog. A lot of time has went into working on his musical aspiration and increasing his fame. He likes to go jogging around the island with his dog. Now recently he also started a romantic relationship with a style influencer who also lives on the island.
- His brother Harry Harmaja lives in Brindleton Bay in a haunted house that also has the trait that stray cats come visiting. Harry is a painter who also enjoys yoga and aspires to be a good vampire. I have been bored with Harry so he has moved from Newcrest to this new house but I'm not sure if I still got it right. Vampires are hard for me to play because they're eternal and it's hard to keep that interesting.
- Billie Jang lives in an apartment in Spice District with her cat and two roommates. The apartment needs some TLC, so that also gives her something to do. She works in charity organizions, but is dreaming of becoming an actress. She also does gaming tournaments for My Sims when she has time. My story from earlier this year tell about Billie's love adventures.
- Urpo Luotto lives in Willow Creek in his uncles old house. He had a girlfriend who had just moved in, but died in a glitchy dryer fire. Urpo got a dog just to get through things. He works in the active police career, but prefers to take his guitar to work and singing while patrolling the streets. I haven't played Urpo much lately, it got kind of heavy after his girlfriend died, but I still plan to play him and hopefully bring some light to his life.
These one-sim households first popped into my head and thinking they're probably the most interesting ones. I hope the examples helped in somehow. Do you count it a one-sim household if they have a pet cat/dog?
Edit: I also should add that these sims are part of my irregular rotation, so I play them when I like and then just don't play when I'm not feeling it.