My expansion pack idea since I see others sharing theirs.

The Sims 4: True blue living

The theme of this pack is blue collar workers, Specifically the new Tradie career type. It would have an Australian themed world, the main appeal is to add several new career options to the game. 

The world would have 3 neighbourhood, one which is more outbook, the second more suburb the last is coastal beach. 

The careers that would be introduced 

• Tradie career, the main draw of this career is you apply for an apprenticeship, having to do learning outside of the career itself, and yes you can drop out of school and take on an apprenticeship. there are 3 branches for the Tradie career; Plumber (focus on Logic and handiness) Construction (focus on Athletics and handiness) and Electrician (focus on programming and handiness).
   Mining career, a rabbit hole career that will have requirements for gemology, if you have crystal creations installed. 
• Postal worker focuses on logic skill 
• Trucker (no actual car, just a rabbit hole job)
• Slacker career, you start as a beach bum and then somehow end up as a motivational speaker, trying to help other slackers get a real job
• council worker (not sure if this is a job Americans have but someone who mows and takes care of public parks and sidewalks and fills in potholes.
• Call center (can be worked from home, you just click on your computer and select take calls)
• Pilot, branches between air force and commercial

Build and Buy catalog 

• for outside objects; Tin roofing, Outdoor water tanks, windmills, a dunny (outhouse) Hills Hoist clothes line (bonus if kids can hang from it and you can play goon of fortune) trampoline, A cubby house for Toddlers and kids, the metal death slide that burns you in the summer, more beach clutter like surfboards, a hammock, Tetherball pole, cricket wickets, ken Kelly inspired lawn decor.
• for indoor objects; things that invoke nan's house, doilies covering furniture, toolbox for tradies, sports memorabilia, a landline, an aircon, an esky (cooler), slot machines, typewriter, Aboriginal decorated objects like a coffee table. 

Create a Sim

• Rattail hairstyle, Mullets, messy bun, messy hair in general, dreadlocks, pixie cuts
• Hi vis work outfits, singlets,  cargo shorts, flip flops, shark tooth necklace, Aboriginal patterned bandana and bracelets, caps, wide brim hats, cork hat, magpie defender (a helmet with zip ties on it)

Reptile collecting

Your sim can purchase a terrarium and either purchase a lizard or snake, or more dangerously catch your own from the while, but you better be good at identifying which snakes are Venomous, cause if you fail to catch a Venomous snake, your sim better have antivenom on hand or they will end up dying. you can actually milk your own snakes for venom and craft your own antivenom if you want to make some money on the side.

Events

• State of Origin inspired night, pub fights, sport team loyalty and a lot of bar drinks happens every few weeks, your sim can pick a team and show your loyalty for whatever team you prefer (could be the sports teams from University).
• Melbourne cup inspired event - Go to the pub and bet on a horse, dress up in a ridiculous outfit, get sad when the horse you bet on didn't win or get a boost if it did. If you have a horse ranch installed you can attend the stadium in person to watch the event or even enter your own horse.
• go gambling - try your hand at the slot machines for a night out. 
  can throw a BBQ event

New recipes

• Pavlova
• Fairy bread
• sausage rolls
• spring rolls
• dim sums
• lamingtons
• damper (new fire pit recipe) 

New lot trait
I also had a new lot trait idea, which is 'poor coverage' your mobile phone/ Cellular phone, won't work on a lot with this trait, you have to have a landline placed and that locks your ability to only call other sims and travel. 

New traits 

• Rugged, These sims are built different, they like more active and hard activities, they recover from injury related moodlets faster then other sims
• Sports fanatic, these sims get a little too into sports, and a little too defensive of their team. 
  Technophobe, these sims do not do well with modern technology, TV and landline is as far as they want to go, and feel discomfort when using their phone or computer. 
• Laid-back, not quite lazy, they are just harder to get mad, they tend to let the insults wash over them. 

New Aspirations

• Tradie legend, reach the top of the tradie career (any branch)
• No.1 sports fan, your sim has shown their support and maybe obsession for their sports team
• herpetology guru, Your sim now knows everything there's to know about reptiles. 

New skills

• Surfing skill but I honestly doubt they would be able to add this one.
• Maybe Glass blowing? or metal crafting? (there isn't that many new skills I can think of) 

New books for sims to read

• Waltzing Amelia (Waltzing Matilda parody)
• The man from Frozen Creek (The man from snowy river parody)
• The Golden Brumby (The silver brumby parody)
• Meredith Doppins (Mary poppins parody)
• Dusty Dill (Blinky Bill parody)
• Daryl the Builder (Bob the builder parody)
• The Bushberry tots (Gumnut babies parody)
• Possum Tragic (Possum magic parody)
• The rainbow turtle (the rainbow fish parody)
• The legend of Ken Gulley (New lore book about the mysterious bushranger of Ken Gulley, a parody of Ned Kelly) 

Premade townies

• The tradie family, 3 mates living in a share house, each a member of the trading career
  The Barley family, an old couple who live outbush, one of their sons who work in the quarry in the area lives with them and takes care of them while their other son lives on the beach in the slacker career as a beach bum.
• The Mackey, a single mum with her three kids, in the suburb area, her teenage son wants to drop out of school and become a tradie, but she wants him to finish school, they have a difficult relationship.
• Kenneth Gulley, an elder swagman who is a roaming townie, with a mysterious past
• Amelia Waltz, a ghost that appears around midnight near the park billabong, has some kind of connection to Kenneth Gulley. 

New dance interaction
This last thing is just a new dance to add to the game, the Bush boogie, which is a parody of the Nutbush. If you start a bush boogie, everyone is obligated to join in, yes it is a requirement. 

But yeah that is my expansion pack idea, I would really like them to expand on careers! I like giving my sims jobs!