I got my seed through Territorial Seed company.
They have a category labeled OP- open pollinated, which they’ve assured me breed true.
For sauce tomatoes, I like the Heinz variety that Territorial sells. They are heavy producers that produce beautiful tomatoes.
I use Jade green beans which are an old non-hybrid variety. Same for purple top white globe turnips.
There are other heirloom seed companies out there but I don’t have any experience with them.
You might be interested in Red_Devil 232 ‘s weekly gardening thread. There are all kinds of people there at all different stages of gardening experience and lots of valuable help.
I’m still just learning about saving seeds. I have a whole bunch of bean seeds from last year and we’ll see how they do.
Neo, I post the thread every Friday morning we have many interests going on the thread and FReepers from novice to Master Gardeners participating. Stop by and chat.