what are some crops required for brewing beer. im looking for main ones?

Hops, wheat, barley and on a lesser basis corn and rice.

Hops Barley Yeast Water the only ingredients needed!

Barley and hops are the two essentials. Other grains, such as wheat, oats, and rye, are sometimes used for their distinctive characteristics. Mass-market light lagers typically use corn or rice to produce a lighter-tasting beer.

Hops