B-complex vitamins include B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin). Foods rich in B-complex vitamins include whole grains like oats and brown rice, leafy greens, eggs, dairy products and fortified cereals. These vitamins play key roles in energy production, brain function, and blood cell formation.