Besides oil watch out for ferts and grains too.
Iran is a major supplier of ferts (Urea)
Qatar is the world's largest supplier of LNG which is used to make ammonia and then ferts.

Who sells a lot of grains? It's the ABCD of feeding the world.
Archer Daniel Midlands
Bunge
Cargill
Dreyfus

Not sure which of these are publicly traded.