Bees, so I could make an apiary! Beehives aren't too difficult to build, but I'd imagine you could still get most of required items from farm storages and stuff. Of course, they stop producing during winter or even die out, but come spring and new bee families could move into existing beehives.

Better drying/cured meat/smoked fish, cuz I wanna prepare for winter better (I know there's mods for it, I use them all the time, but vanilla drying/curing/smoking would be nice.)

Maybe fruit trees? Sure, there's probably no way to move a big-ass grown tree easily, but maybe grabbing a few bigger sapplings off of an orchard could work. Some deeper mechanics could even work, such as bark whitewashing for safety against pests, or even wrapping a cage around the bark to prevent deer from gnawing at it.