Hi Elizabeth,
A couple of less-common options that are biogenic (and therefore carbon storing) would be:
- Resysta, a board-style cladding made from rice hulls, mineral oil and salt https://hdgbuildingmaterials.com/wp-content/uploads/2016/06/Resysta-Decking-HDG-Building-Materials-503-360-9551.pdf. This one is available in the US.
- Margent Cladding, a corrugated sheet made from hemp fiber and plant-based resin https://www.margentfarm.com/journal/hemp-fibre-corrugated-panels. Currently made in the UK, they are keen to expand into North America.