The main list is here.
Before I explain my seed selection choices, I need to take a moment to explain how I lay out my garden. I'm a firm believer in crop rotation, so I tend to plant members of the same plant family in one bed. And then I'll plant something different in that bed in the following years. Crop rotation can help reduce pest levels by interrupting life cycles and can also help with soil nutrients. For example, legumes fix nitrogen, so planting brassicas in a bed that had beans or peas in it the past year will help the brassicas grow better, without having to add any fertilizers (assuming one leaves the legume roots in the soil, of course!)
These are the main plant families in my (and most) gardens:
Alliums - onion family, including garlic and leeks, and perennial plants like chives
Solanums - tomato family, including peppers, potatoes, tomatillos and ground cherries
Brassicas - cabbage family, including kale, broccoli, mustards, rutabaga, turnip and radish (among many others)
Cucurbits - squash family, including winter and summer squashes and cucumbers
Legumes - bean family, including peas and uncommon crops like peanuts, lentils and chickpeas
Asters - in addition to the flowers, this includes lettuces, sunflowers and perennials like Jerusalem artichokes.
Chenopods - beet family, including spinach, chard and quinoa.
Umbles - carrot family, including parsnips, celery and celeriac, and a lot of herbs like dill, chervil, coriander, fennel, lovage and parsley.
Malvas - okra, and flowers like hibiscus and mallow
There are other plant families which may be present, of course, but they tend to be either unusual choices for backyard gardens, or herbs or perennials that aren't included in rotations.
Clear as mud, right?
Most people, when first learning about plants and gardening, get hung up on the scientific names. In other words, why say solanum when you can say tomato? Because all tomatoes are solanums, but not all solanums are tomatoes, of course ;)
And also because I'm a total plant geek, and after umpteen botany courses and years of working in the field, I simply think in these terms. These are the terms I use for the families in my garden, and which work for me, even if they may not be 100% correct (example: the Umbels are more properly known as the Apiaceae, but I remember them as umbels, since that is the name for the flower type they produce, and the old name for the family).
You don't have to know, or remember, the correct names for everything you grow, but if you want to do crop rotation, you do have to know which plant belongs to which family*.
Up to a point.
Because it also depends on how your garden is set up and how much of each family you grow. I'm never going to grow an entire bed of lettuce, for example, or of okra. So I tend to have at least two beds of "mixed" plants, but by always keeping those mixes the same, it works into the crop rotation. I plant one bed with half beets and half carrots, and one bed includes lettuce, spinach, celery, celeriac, chard and any other oddball plant- like okra. The herbs, of course, are off in their own bed, so I don't worry about them for crop rotation.
Going forward, I'll be discussing my seed selections in more detail by group, so I thought I'd get this out of the way first.
Besides, everyone should be doing crop rotation, right? ;)
* I have recently seen a plan for grouping crops by "niche" instead of botanical family. So, all root crops would be grouped together, all leaf crops together and all fruit crops in a third group. While this is easier to remember, I do not recommend it, as it doesn't, in my opinion, adequately rotate crops. For example, "roots" can include members of the brassicas, cheopodes, umbles, alliums, and if you stretch the definition of "root" far enough, solanums (potatoes), asters (Jerusalem artichoke) and legumes (peanuts). Leaf crops can include brassicas, asters, chenopodes and umbles. Fruit crops can include legumes, asters, solanums, cucurbits, and malvas. How do you properly rotate that?