• Chicago Board of Trade
• The trade rules in the Chicago Board of Trade rulebooks list only warehouse receipts or shipping certificates as the deliverable instruments on contracts, depending on the futures contract in question. (Corn futures require a shipping certificate as the deliverable instrument.)

• grains, biofuels, oilseeds, fertilizer https://www.cmegroup.com/company/designated-contract-market.html#cbot

grainstats.com/futures-part-ii