Corn is profitable, but on a large scale. Same with soy beans. You need more than 45 acres to make it a free standing business. Hay can be profitable in some years, not so much in others. I contract grow 60 acres of pop corn and see a fairly health return on that, but much of my equipment cost is shared with acreage of feed corn and soys.
I have a couple neighbors who courted and developed a market for various veggie crops. (ie Broccoli, cabbage, tomatoes, ect) You need to research local markets to see if there is a buyer before jumping on that bandwagon though.
My son has 35 acres of trees and shrubs, raising them under contract for a landscape product vendor. He's liking the results of that venture after 3rd season.
Also, a local sod business has several farms growing turfgrass sod under contract. Down side is, unless you have deep top soil, your land will be depleted of good soil in a few years. But, the money is good.
University of Kentucky is really promoting blueberries as a cash crop. A number of former tobacco farmers in my area have made the switch and are just now starting to see significant returns on their investments.