100 Baby Challenge (Official)
A challenge based on getting the fewest matriarchs possible to have 100 (or more) babies.
By: Snarky Witch

7 Sins: A Redemption Challenge
A challenge to take 7 ghost sims, each representing one of the seven deadly sins, on a journey towards redemption.
By: Shadami

Baby Boom Challenge
An single generation challenge to have a pair of parents raise a minimum of 24 babies - 12 girls, and 12 boys.
By: itsjulie and Thaitanic

Board Game Challenge
An 8 generation challenge based on several board games with generational goals.
By:JavaBeanDreams

Build Newcrest Challenge
A 10 generation challenge based on rebuilding Newcrest.

The Drifter Challenge
A 24 generation challenge with both sim and building goals. Aims to rebuild both Willow Creek and Oasis Springs.

by: Vihisha

DyNasty of Darkness Challenge
A 5 generation legacy challenge with the goal to build a super creepy house and the "ugliest" family of monsters you can.
By: Livvielove and itsjulie

Evolution & Progress in Change (Epic) Challenge
A 10 generation challenge with goals and possible points as well as having lots of choices throughout the challenge, making it completely replayable.
By: Teresa

Five Year Celebration Legacy Challenge
A legacy challenge created to celebrate 5 years of Sims 4. Each generation has goals based on the packs we've gotten.
By: PhD Simmer

Globetrotter Challenge
A single generation challenge meant to take your sim on a journey of discovery around the sims worlds.
By: Moonfi

The Great British Sim Challenge
A Sims 4 History challenge that takes you through the history of Great Britain.
By: Emersed Crown

The History Challenge (Official)
A 10 generation challenge with two difficulties that takes you through history from the stone age to the future.
Originally by: Cloudseeker

I'm Surrounded By Idiots (ISBI) Challenge
A super fun and choatic challenge where you only control one sim in the family, and everything the other sims do is scored with positive or negative points. Goal is to make it 10 generations.
By: Lynnwood

Magikal Witches Legacy Challenge
A 5 generation challenge of spellcasting fun and chaos.
By: RoryPlays

Name Game Challenge
A challenge adapted from a Sims 3 challenge where you start with a founder, and use the letters of that name to name their children, then the heir's name to name their children, etc. The goal is to get through the whole alphabet in the fewest generations.
Adapted By: Cynical Badger

Neck of the Woods Challenge
A challenge based on exploring all that the game has to offer through building and populating different neighborhoods throughout the generations.
By: PatchyStraw

Packs Legacy Challenge
A generational challenge to work your way through the sims 4 packs and, hopefully, experience game play you've never seen before.
By: SyddyB206

Parentcy Challenge
A generational challenge where each parent has different methods and goals to complete.
By: CookingPup99

Rags to Riches Challenge
A single generation challenge where you take the sim of your choice from living in rags all the way up to riches.
By: SimishGamer

RainbowSin Challenge
A 10 generation challenge based on playing evil sims and the 7 deadly sins.
By: DaisyDezem

Time of Your Life Legacy Challenge
A challenge to experience as much of the game as possible and to live meaningful, eventful lives with your sims.
By: AlienNooboo

Vampire Lineage Legacy Challenge
A challenge to have a vampire legacy based on a backstory.
Originally by: Pinstar

The Victorian Challenge
A rotational challenge to simulate the ups and downs of the Victorian era as accurately as you can gameplay-wise in the Sims.
By: The Sims Library

More coming...