Hey, /out/. Here's a hypothetical for you.

You can have 5 plants for a farm. The farm has infinite space and the soil quality never degrades. Climate is not a factor (you can grow cacti next to cloudberries, if you desire). Disease is a factor. The plants can be extinct. You can sell your plants, but you cannot buy new varieties or new plant related materials like wood, seeds, cotton or plant oils. You do not have domesticated animals, but wild ones are fair game (for example, you couldn't have an apiary, but you COULD try to attract bees through roses or something). In this farm, you already have an infinite water well, a house with utilities, electricity and so on, but you do not live close to a city, as this is a large farm. You have no taxes to pay and have indefinite time.

Which 5 plants do you choose?

Here are mine:

Blood amaranth: useful for flour, popcorn and porridge. Their leaves can also be used similarly to lettuce or spinach. I imagine the stems would make pretty good forage or silage. I also imagine they could be used for alcohol production, but I have no evidence for this.
flax: Flax is used to make linen. Linen is stronger than and more absorbent than cotton, so it does double duty as reliable clothing or cloth and as rags. The flowers are also edible, if I remember correctly. It'd also be good for rope and string, obviously. Seeds can make flaxseed oil, which is useful for cooking and shit.
sugarcane: i was torn between this and agave for a while. While agave has big flowers and sweet (useful for bees), as well as use in pulque, mezcal, sugarcane is used to make rum, molasses and is easier to process.
potatoes: i dont think i need to justify potatoes.
tea tree (or coffee, if youre so inclined): caffeine, as well as wood.