Using sheathing as siding?
Although this is asking for product recommendations I think discussing different types is ok. I have not used Hardie Board without sheathing but believe it is listed for use without sheathing. A buddy of mine really likes the cement panels they make. I have not used it but he started using it ~10 years back I have used their plank products when properly installed it looks good for decades. (It really holds the paint better than wood products on the work I have done).