Every year I try to save seeds from certain vegetables, and some strains I have been saving for many years now. I've been keeping the Lord Leicester peas going for ages, though this year we ended up eating most of them fresh! I got a few dozen only, but I do have quite a lot from last year which should still be viable next spring.
Another one which I have been growing for several years is the green Kuri squash. We cooked the biggest one from this harvest already (it met with a little bit of damage during harvest and couldn't be stored) and the husband put the seeds to dry for next year. It came in at around 4 lb; while it's a good size for us, none of the others are even half as much. So to try and get the biggest squashes in the future, we saved the seeds from the biggest one harvested.
I grew two new to me varieties of French beans this year, and have saved seed from both of them; one is a long podded purple type and the other is a flat podded green type. Both tasty and fairly productive. I'm moving away from runner beans--my usual green bean in the past--to French beans as they tend to set beans more reliably in dry summers. That's not to say I won't grow runners again, but I didn't grow any this year.
Another new to me plant was the yellow crookneck squash, which was not as productive as I would have liked but such a tasty vegetable that I allowed one squash to mature fully for seed; the rest were eaten as young courgettes. I still plan on trying to cook this lumpy yellow squash--we'll see what it tastes like when mature, but regardless, seeds will be saved.
Not seeds per se, but still continuation of the strains: this year I saved and have replanted garlic cloves and leek bubils.
I have also acquired some seeds of a huge cabbage (and a few more leek bubils) from a fellow allotmenter, and have a very large Cinderella style pumpkin from the local farm stand, though we'll have to taste test it first (after we attempt to carve it later in the week--it's not a traditional Halloween pumpkin and might require a hatchet to get inside); while I'd love to grow some big carriage-like pumpkins, I only want them if they taste great too.