Plant Families

So after reading this super helpful thread https://permies.com/t/49696/permaculture/Roses-permaculture I learned about how well roses, apples, pears, strawberries, raspberries, brambles, etc grow together because they are within the same plant family, which made me want to ask all the knowledgeable folks here at permies what other great family members they had found to benefit each other? On one hand, this seems like a type of companion planting, but most companion plants that I had researched weren't necessarily related to each other. That's why I found it so interesting. I'm the type of person to overlook some of the simplest things sometimes, so it's no wonder I never thought about planting family members near to each other.

Family members grow well together mostly because their ideal growing conditions will be very similar.

Guilds and companions ( three sisters and the like) grow well together because of the symbiosis the plants have and because their ideal growing conditions are similar.

If you planted a field of different brassicas as an example, they would all do well because of their needs being almost alike.

If you took the many different plants of the nightshade family and planted them together, the same would be true.

What I look for when creating a guild are plants that 1. won't be competing with each other for, space, sunlight, particular nutrients, etc.
This would be ideal and there are many options that fit this criteria. Another way to create a guild is to look for plants that will react in a symbiotic manner, this means that plant A does things that benefit plant (s) that I want to put in close proximity.
Corn, beans, squash have a symbiosis since the corn will support the beans growing vines and the squash will benefit from the partial shade of the corn and beans. In this three sisters set, you also have nutrient availability sharing, the corn needs lots of nitrogen, the beans help the corn get that needed nitrogen along with micro nutrients. The squash also benefits from the beans nitrogen habits and the squash also helps the beans by making more micro nutrients available to the beans and corn. The corn is the one plant in the three sisters that takes more than it gives, but the support and partial shade are so valuable to the other members of this trio that it all works out fine for all three.

Garlic and Onions can grow well together but they don't play so nicely with others because of their Allelopathy towards some vegetables and trees. They do play nice with sweet potato, tomato, some of the squashes, and to a certain extent some fruit trees. It is fairly easy to
develop guilds that will be very symbiotic and thus out produce a "mono" crop type planting setup.