... spring?
Title pretty much says it all.

Pear trees are pretty much idiot proof

Berry bushes? You may get overrun though

Strawberries

Asparagus. My artichokes are huge and come back, they need a lot of space, but not much love. Very pretty too, good for the back of the garden. Strawberries.

Blueberrys, huckleberries, muscadines

Move to Hawaii.  Mangoes, papaya, guava, lilikoi, oranges, limes, lemons, grapefruit, bananas, coconuts, and lots more.  

Even with berries they need some care to thrive. Blueberries should be pruned every year for berry quality. Raspberries need to have old canes removed to help prevent disease and tangled mess, blackberries same thing. Strawberries need to be rejuvinated periodically.

Actually, it doesn't.  We need to know which grow zone you live in.

Blueberries are great as you don't have to remove old canes like blackberries and raspberries.  They're probably the least amount of work other than some minor pruning as already noted above.

Rhubarb is more limited in what you can do with it, but it grows back every year and requires minimal maintenance other than some fertilizer and removing dead leaves.

Asparagus was mentioned.  It's time-consuming to prepare and plant and you can't harvest for a couple of seasons.  But after that all you need to do is fertilize and remove the dead stems.

Walking onions
Shitaki mushrooms

On the contrary, you absolutely HAVE to prune Blueberrys, to maintain production, and health.

After 6-7 years, a Cane will consume much more nutrient content than a 4yr old Cane that will produce more fruit, and new fruiting growth.
Eventually, it leads to a reduction in health, and disease resistance.

In addition, pruning to avoid damage, and getting rid of diseased canes has to be done. Phomopsis, Alternaria, and Mummyberry infected tissues serve as an incubator, and will lead to a rapid decline. Phomopsis and Mummyberry shoot strike can both cause rapid decline.

Taking out 3-4 of the oldest canes, and then clearing the middles for air movement, in the Fall/winter creates a flush of new new cane Growth from the crown, and new growth on existing canes. 2yr old growth produces the fruit. Maintaining the cane age range, from 1 to 8 years also keeps the crown expanding, and new root development with it.

Done right, it takes about 5-10Min per bush to prune every late fall. Not real bad, unless you have thousands of the things...
Still beats dinking around with Blackberry/Raspberrys though.

Asparagus and rhubarb are the only perennial plants that I know of.



Aside from that, you'll be relying on fruit and nut trees or bushes.  When I was growing up we have a large area of blackberry and raspberry bushes.  We never really did any sort of pruning to them or anything like that, just let them do whatever but for any of these you'll be waiting a few years before you see anything.  Better get started now.  The only other thing I can think of for advice might be if you decide to plant apple trees, my understanding is that fuji apples are pretty naturally resistant to pests.

Here is what I can think of off of the top of my head.  You might want to get a book on perennial vegetables if you are serious about the endeavor and want more than fruit and nuts.  Some of these sound exotic but if you google them you will find a whole world of foods out there you never heard of.    I wouldn't suggest planting acres of something you have never tasted, but a sampling of this or that might be an interesting endeavor if you have the space.

scarlett runner beans
hyacinth beans
climbing variant of lima beans
asparagus
artichoke
chinese artichoke
cardoon
walking onions
rhubarb
sunchoke
nut trees
fruit trees
berry bushes
herbs
tea (camellia sinesis, not tea tree)
napale cactus
horseradish
arrowhead (aquatic)
skirret
zuiki taro
tree collards
good king henry
air potato (hardy to zone 7)
yams (not the same thing as sweet potatoes)
ground nut (NA native)
water lotus

Sunchokes / Jerusalem Artichokes

I dunno, my ~10 year old asparagus bed is in constant annual battle against weeds.   I'm still trying to find the right combination of mulch material and thickness to let the asparagus poke through but keep broadleaf weeds from overrunning the bed.

It's worth the struggle, though.  

Pawpaw trees, if you have a creek or something. They use a lot of water I've heard. I have a patch of about 30 trees in the woods growing along both banks of a creek. When I remember to go harvest them, I usually get more fruit than I can carry out.

"Permaculture" is the word you are looking for.

My grandpa just put a bunch or road salt on the asparagus beds, had to renew it every 3 years or so (whenever the weeds came back). Asparagus does't necessarily LIKE salt, but it tolerates it, unlike its competitors. Not sure how much to add though, I was relatively young and didn't really care for asparagus.

Seriously?   I had no idea yams came back every year.  I'm definitely going to remember that one, thanks.