Highest yielding perennials? Which ones not really worth the crop?

What are the highest yielding perennials? I've heard Good King Henry is on the upper end of perennial yields. Which ones have you seen recommended, but were so disappointing in yield (or taste) that you wouldn't recommend them?

Best yielding where? How long a period of time? What type of yield?

For me, so far the best are Walking Onions, Elephant Garlic, and Asparagus. Asparagus will survive here through severe drought with no irrigation, though it will not produce under those conditions. But it is unkillable.

I found a site in the uk that does a cut and come again cauli (victorian nursery) You only need a couple of plants but they do get quite large and they last for about 5 years,

i agree with the walking onions and asparagus, no one mentioned Jerusalem Artichokes, never saw a higher yielding perennial. also Daylillies are quite high yielding and mallows, violets, good for salads..and quite prolific.

I believe lambsquarters is an annual but it reseeds and is quite high yielding.

and then there are fruit and nut trees which are perennial and generally are very very high yielding, berries and grapes as well. they do take a while to start providing but once they do they last a long time..but never hurts to plant their replacements in advance as well.

Basically nut and other fruit trees. A couple of trees of each species and you end up with heavy crops.

Also think staple-wise. Nuts can be used as a staple food. One tree produces as much as same area of grain. And you do not need to care for it, once established. Waiting time is key.

Avocados. Perennials beans and pulses like siberian pea, mesquite, pigeon pea...

Mushrooms, once established in a favorable area, just keep on doing their thing and making food. Not to mention all that great work they do in the soil. And, mushrooms (fungus) are one element which micromanages our soil for the optimal growth of the other elements in the garden. I would imagine that this would mean more stability in the garden and higher yields from other plants and trees.

It depends what you want. Jerusalem artichockes are prolific, but how much do you really want? They are not terribly good unless your want to burn schnaps.
Rhubarb is really worthwhile and grows in shade. Small fruits like currants or strawberries. The same with greens like sorrel or mints you only need so much.I will try air potato and kudzu both sound promising and can be used as staples. Chestnuts but the trees are huge.

Scarlet Runner Beans come up from the fleshy roots every spring, so once established they just need something to grow up. That could be a bush or a twig Trellis or a wire grid etc. They bear well in cool and warm weather, but not in hot weather. Where I live in California they bear both before and after my regular green beans. They put out a lot of green beans in a small amount of space. They begin to die back when it gets cold and completely die to the ground when there is a frost. They do especially well in Great Britain.