When I played The Sims 3, most of the time the game would give me some storylines ideas, there were always unexpected things that affected my gameplay and I felt my characters were alive and had personalities.

They had their preferences and did things I never told them to do. I enjoyed following their whims and the random unexpected things that occurred; that is why I loved The Sims 3 so much.

In The Sims 4, I often struggle with ideas for my new character’s personality, goals, and storylines.

But I found a few useful things for how to generate more ideas for the new families I create, and here I’m going to share these tips with you:

Sims 4 Character Generator

I have recently found this generator that allows you to generate a life story for your sims. It randomizes the city where your sim grew up, their traits, life goals, jobs, their likes and dislikes, what kind of pet they have, and who they live with. I think this is useful and can make your stories more interesting.
https://perchance.org/s4generator

Cas wheel

This generator allows you to choose packs you want to include in your randomization. It contains appearance, traits and aspirations, career, social life and more.

https://thesimschallenges.wixsite.com/sims/cas-wheel-spin?lang=en

Ingame activity generator

If sometimes you feel bored and don’t know what to do in the game, you can use this generator to randomize an activity and create more fun and action.
https://papasitaa.tumblr.com/ros

Appearance generator

If you like to create unique and pretty sim models, this generator helps you with ideas for their appearance; their clothes, hair color, skin color etc.
https://www.seventhsanctum.com/generate.php?Genname=generalperson

Appearance, personality and plot generator

Here you can find several generators for a quick character description or a detailed description, personality, and cause of death.
https://www.character-generator.org.uk/

I hope these tips were useful and make your game more fun!