Point of clarification: I believe he means Relentless Rats, not Ravenous (not that being able to run 5 Ravenous Rats would make a huge difference...).
Here is a link to the "official" Peasant Magic rules, which includes a banned list:
http://www.geocities.com/peasantmagic/rules.htmOne notable change from that website is the ruling that, although Strip Mine
has had a common version printed, it will be treated as uncommon for this format.
The cards that have been banned are: prohibitively expensive for most people, format disrupting, or were printed in sets that didn't have rares (but the cards in question would have been considered as such).
For convenience, here is the banned list from that site:
Jeweled Bird Timmerian Fiends
Bronze Tablet Brain Freeze
Ali From Cairo Bazaar of Baghdad
Berserk Candelabra of Tawnos
Diamond Valley Juzam Djinn
Library of Alexandria Mana Drain
Mishra’s Workshop