I do save seeds from my favorite pole bean. It is a flat Roma type. It is very flavorful. The advantage of pole beans is that they are steady producers over the summer. There are enough for a meal every few days. Bush beans are bred to have all the beans be ready to harvest at the same time for commercial growers. Flavor is a secondary consideration. A home grower gets more beans than can be used, then nothing. Pole beans do take longer to start producing, so I plant some bush beans to provide a first crop until the pole beans are ready.
I also save garlic bulbs from the current crop for the next year. I grow two varieties of hard neck garlic plus elephant garlic. I have no idea what varieties the hard neck are. They were given to me years ago.
In Wisconsin, garlic is ready for harvesting in late July or early August. After harvesting and letting them dry out I select the largest bulbs for replanting. In mid to late September I plant them for the next year.
Elephant garlic also produces hard little bulb like things outside the main bulb. You can plant those and the next year you will end up with a single section bulb sort of like an onion. You can plant that for the following year and end up with a normal multi section bulb. I usually just eat them.
Saving vegetable seeds can greatly reduce the costs of gardening. You can save even more by buying discounted seed packs at the end of the season and putting them into the jar in your refrigerator right away.