The most productive things I grow (temperate/cool climate in coastal BC) and then actually eat/enjoy:

- Zucchini always grows more than we can use, but they're really good. I pick them very small (~6") so the plant continues producing and growing more

- Chard grows year-round and is very resilient and low-maintenance. It's great in casseroles, soups, sautees, and other cooked formats

- Kale is similar. It'll just keep on giving

- Bush beans are amazing in summer, and if you've got vertical space, pole beans can be incredible producers too. My 8 foot raised bed has a single row of pole beans, and I've been harvesting from them for about 6 weeks with plenty more to come. This single row is very densely planted, but I feed it heavily and ensure it's fully exposed to the sun. With enough nutrients and water, you'll get pounds of beans. Again I pick them relatively small and often

- Nasturtiums make a beautiful flower but the leaves and flowers are incredible in salads, and their seed pods can be used to make a really delicious pickle/ferment as well. Throw them in hanging baskets and use them to make fun salads

- Scallions are a fun one that can be densely planted and only need 6" or so of depth. Bulb onions can be a bit more sensitive and demanding, but scallions are pretty easy going. I stagger the plantings throughout spring so I can harvest bunches of them every few weeks. They never seem to do poorly

I grow lots of other stuff but I don't always eat or enjoy them as much as these things. One exception is lettuces and other greens/herbs, but I grow those hydroponically indoors because it allows for a system that makes timing and harvesting much easier so I'm more likely to ensure it doesn't go to waste