The larger updates since launch...
Hearth and Home (this is where I started) adds a great deal of base-building options, a new mob and resource in the plains, and revamped the food system.
A smaller update in late autumn added a new mob to the swamp, a new resource, and new armor.
A medium update in late winter added mountain caves, a dungeon in the mountain. This came with new mobs, new materials, new armor (that's great for working at the base) and a few other things.
Lots of spoilers for the Mistlands update have been slowly leaked... but the delivery date on this has constantly been pushed back by the devs' ambition. They're promising a lot for this, which means they need to take the time to actually deliver, which raises our expectations, which means they need to take the time to actually deliver, and as far as I can tell we're in an infinite spiral here.

Oh. And Lox saddles. Don't forget lox saddles.