I saw something like this a while back. I dunno whether its the same idea. That said in terms of gut health and plant based products, herbs, spices and grains counted too (either fresh or dried). It might not be for this particular plan, but that was my understanding. It didn't have a minimum quantity, just that you needed to consume it. When I included them in what we already ate regularly it was quite surprising.
If you do bread, you can include multigrains or seeds in your list too - so poppy seeds, sesame seeds etc. I've just looked at a bog standard loaf of multigrain you can buy for 85p - its got Sunflower Seeds, Golden Linseed, Millet, Pumpkin Seeds, Poppy Seed in it. Thats in addition to Wheat, Soya and Barley being on the ingredients list. So there's 8 in just one item. Just 22 to go.
Add in herbs and it makes it MUCH easier to achieve than you think. That gives you thyme, basil, rosemary, cumin, parsley, sage, mustard seeds, coriander, chives, dill, paprika, chillis, fennel, pepper, oregano etc etc.
Herbs have a reputation for being expense. They aren't if you either buy in bulk, at a speciality worldfoods stores or you grow your own. Lidl do cheap seeds in Feb/Mar and the last few years you could pick up herb seeds from 20p a pop. Wilkos are also really good too. You can grow on your windowsill or very easily in pots outside - no need for a big garden. And then you can dry and store for the winter.
Even a bog standard mixed herbs from the supermarket will typically contain Thyme, Marjoram, Oregano, Parsley, Sage, Basil. Thats 6. You've already got the ones in your bread. That takes you down to only needing 16 more plant based foods. Even if you don't count them as a full plant based food it still helps crank up the numbers, especially if you eat several times a week.
So season, spice and herb your food, switch your bread and you are a massive way through your quota for the week.