Challenges to do

If you're up for something difficult and long you could try the Apocalypse challenge.

Or, for something simpler and quicker, what about one of the in-game scenarios? There are beginner, easy or intermediate levels to choose from.

DarkEmpy​ What kind of gameplay do you enjoy?

I really enjoy Rags to Riches, which can really be anything you like (I often stop/get bored once they have a functional house, and start over with a new sim) and is great with Seasons and Cottage Living! You could make it extra challenging by adding Simple Living Lot Challenge, and/or starting in winter!

The one month one world one year challenge is the most fun one I've ever done. It is pack heavy, but since you only have 4 worlds, you could do Feb - March in Willow Creek, April - June in Oasis Springs, July - Sept in Newcrest and Oct- Dec in Henford on Bagley. It's here: 

One Month One World One Year Challenge 2026 | EA Forums - 13045275

You could try a legacy too, there's lots of different variations. 

There's also a thread with a bunch of different challenges in it, though it's not been updated in awhile, but you might find something you like there. 

https://forums.ea.com/discussions/the-sims-4-creative-corner-en/sims-4-challenge-list-updated-may-24-2021/2272441

How about a decades challenge? That is my favorite. If on PC you can get cc to match every decade or you can just play with the rules of each decade. It is my favorite challenge because of the restrictions you need to play within for each decade. 

DarkEmpy​ There's also the Every Death Challenge. With base game, Seasons, and Cottage Living, you could challenge yourself to up to 16 unique deaths! There are a few you really have to work at. You can find the full list of deaths by pack at https://help.ea.com/en/articles/the-sims/the-sims-4/sims-4-deaths/#deaths-by-pack

A twitch sims 4 streamer mentioned the evil chicken challenge on one of her streams. So I looked it up on Google:

The "evil chicken challenge" is a community-created gameplay concept in The Sims 4 that typically involves the goal of raising a specific number of evil chickens or building a scenario around them, utilizing features from the Cottage Living Expansion Pack.

How to Get an Evil Chicken

To get an evil chicken, you need to acquire an Obsidian Egg or feed an existing chicken a Midnight Treat.

Obtaining an Obsidian Egg

Relationship Status: Hens that are very happy but have a bad relationship with their owner have a chance to lay an Obsidian Egg.

Treats: Feeding a chicken a Spicy Treat can result in a hatchable Obsidian Egg.

Hatching: Place the Obsidian Egg in a chicken coop to hatch an evil chick, which will grow into an evil chicken.

Using a Midnight Treat

Purchase: Midnight Treats can sometimes be purchased from the garden stall in Henford-on-Bagley or a grocery delivery person.

Crafting: Midnight Treats can also be made using a Cowberry Jam and an Obsidian Egg.

Feeding: Feeding the treat directly to a fully-grown chicken will turn it evil.

Evil Chicken Abilities

Protection: You can ask an evil chicken for help to protect your home from foxes, household enemies, vampires, and even the Grim Reaper. They can get into a fight loop with the Grim Reaper, potentially preventing a Sim's death.

Laying Eggs: Happy evil hens will always lay Obsidian Eggs.

Mean Interactions: Performing multiple mean interactions on a chicken can provoke it into attacking, which can even result in a Sim's death if you push it too far.

Challenge Ideas

While there isn't one official "evil chicken challenge", players have created various scenarios, such as:

The 100 Chicken Challenge: A variation of the 100 Baby Challenge, focusing on raising 100 chickens, including evil ones.

Rags to Riches: Incorporating evil chickens and their unique eggs into a rags-to-riches storyline.

Evil Lair: Building a specific area or "island" to contain and manage a collection of evil chickens.

I am in the early stages of playing this myself and am finding it alot of fun. Maybe this would be an idea for gameplay? 

For a quick one I recommend the Family on a budget challenge. A sims couple must raise six children on only a single part time job income. No other form of generating money is allowed.

Traveling is unlocked by paying 200 simoleons for a bus ticket (one time fee), clothes cost money (50 simoleons per piece). All sims must have a cake for their birthday, they need at least one friend outside the household and complete one child aspiration. That's it already for rules.

If you haven't I'd also recommend trying one of the scenarios for quick gameplay!