Saving seeds

Most reliable are French beans and peas because they self fertilise with in the bud before the flower opens.
Then tomatoes as they usually pollinate themselves, helped by tapping the canes, to release pollen.

All the others need pollinating by insects, so will readily cross pollinate - which means that you don't know what you'll get next year, if grown alongside other varieties.

In the past most people grew a crop of let's say, cabbage, all would be the same variety, so next years plants would be quite uniform. Nowadays there are many varieties grown, within a small area,. so cross pollination is bound to occur. Any saved seeds would still be cabbage, but not of the same variety, or standard, of the ones you grew in the first place.

If you want to save seeds (only from non f1s) then you need to isolate your plants, with fine netting, to stop cross pollination. Otherwise I don't think it's worth it tbh

some good advice here
http://www.realseeds.co.uk/seedsavinginfo.html

I have saved bean seeds, peppers, onion, aubergine, courgette, butternut squash and tomato to sow next year.

As Mum says, if you isolated the flowers (male and female for the courgette and squash) then you've got great seed for next year.

If you didn't, it might well be a bit hit and miss as they could well have crossed with other varieties. I wouldn't bother growing things I am not absolutely certain are true - at least not the bigger plants of the selection you mention. Tomatoes and beans I'd probably take a punt on.

Personally I love seed saving. It's my new hobby on the allotments, but I'm a bit challenged for space, given you are advised to grow a certain number of each variety you're saving just to maintain the plant vigour in its offspring.

Being hybrid plants, you won't know what their offspring will be like.