Eggs are such an interesting example to me. I'll speak mostly to the US here, but a good chunk of the population could absolutely raise their own chickens for eggs I'd they really were interested in an easy way to reduce impact. A flock of 6-8 hens don't require too much space, and ideally you can use them as bug control and fertilizer replacement in their lawn.

I live in an area with quite a few commercial chicken houses. Its an absolutely disgusting industry today, from how the animals are treated to the nasty conditions workers have to deal with. Getting rid of plastic and styrofoam packaging would be a nice win, getting rid of at least a portion of the market for industrial bird operations would be the real win in my book.