Richard Mabey wrote a very useful book in this regard, and you can read a good chunk of it (also for free) here.
Foraging is also very much part of some cultures, and even a necessity for many who can not afford to purchase food at all.
Tens of millions of Africans rely on bushmeat.
This has caused issues in the past - the consumption of 'bush meat' being a factor in the outbreaks of Ebola in West Africa, such as the outbreak in 2014.
