Home grown fruit/veg suggestions please

So I have heard the reports that meat is high on the carbon footprint scale, although I believe chicken isn't sooo bad.

But I also received an email from an online 'heritage butcher' that I've used before. The owner is starting a campaign called 'Save our Season', to try and lobby for a seasonality tax. The idea being, we pay x for British Asparagus, and y (which is nigh on the same) for imported asparagus, when British isn't in season. I say asparagus... I do use lidls as well as waitrose...

But this got me thinking... his aim was it would promote reduced food miles, seasonal eating and quality/welfare. He also suggested that the commonly published footprints for various meats aren't what they appear... as they take into account the average food miles as well as cow farts...?

I'm not anticipating getting any livestock, but I am wondering how much of our veg I can grow myself?

Has anyone got some suggestions for useful things to grow? (That are legal!) I'm going to have another go at Trinidad Perfume Chilli's, and I've got a good stock of Red Bull sweet pepper seeds from the last couple of years. But trying to think of some more things to grow, in particular (but not limited to) those that tend to be imported (?)

I'm also tempted to have another go at growing mushrooms, but probably from a proper kit rather than grain spawn like I did last year...