Some of the best tomato seed varieties are often patented, e.g. F1 hybrid sungold tomatoes (though reproducing those is also annoying because they are a hybrid and people generally want seeds.) There are groups[0] which try to make varieties as heirlooms (i.e. collect-and-plant) seeds that are copyleft licensed[0].
For another interesting example of recent plant developments, Norfolk Plant Sciences developed purple tomatoes and recently began selling seeds of them. Unlike other purple tomatoes (of which there are only a few) these have purple meat inside, incorporating a gene from snapdragon flowers, which also keeps the tomatoes good longer. They are patented, $20 for just 10 seeds.
Another small company, Baker Creek’s “Purple Galaxy” tomatoes, has been suspected of re-selling Norfolk's purple tomato seeds and recently stopped selling them due to 'low stock' (suspected cease-and-desist) - as a minor controversy in the gardening community last week, though allegedly Baker's Creek is a white nationalist group so YMMV on whose side you want to take there.
Anyway, plants are fun!