Aye, welcome back~
Definitely depends on what you'll be into. I've enjoyed City Living from the clothing, food stalls, new recipes, culture to new semi-active careers as well. Think the only thing I was disappointed in is that apartments are just restricted to San Mynshuno other than that I do like having my sims live there.
Gamepacks are pretty great and focus on the theme they're given.
Vampires is pretty well praised. The gothic century furniture to victorian like clothing with some mixes of modern clothing is definitely a must. Forgotten Hollow is a small neighborhood, but aesthetic wise it's a great place for more darker and spooky surroundings.
Spa Day has been a favorite of mine since I use a lot of build/buy items from it and there's a lot of nice athletic gear to choose from plus sims being able to do yoga and meditate if you don't want them always getting beefy on a exercise machine.
With Expansions I find Get Together and Seasons to be really
great additions.
The UI Mod and MCC mod are just must haves to make things handy.
LittleMsSam is a great mod creator to look at who has a lot of mods form small fixes to extra additions.
SACRIFICAL is also a well known modder who's know for the Road to Fame mod. Basically like a celebrity mod, which is pretty big and he's always adding onto it and adding other features. Never seen a mod this big with so much put into it.
No need to transition from Sims 3 if you still like playing it I still play older games myself. Though I found it hard to go back to playing older games, especially 3 with how multitasking works in Sims 4. Never knew how much I need sims to be able to sit, eat and talk and even watch tv at the same time without interrupting animations. It's just amazing.
