Hi,
You can check all approved nova specifications via the following link:
https://specs.openstack.org/openstack/nova-specs/
With that, there are also a couple of specs which were proposed but not yet approved here:
https://review.opendev.org/q/status:open+project:openstack/nova-specs
Hope this helps.
Where can I find the nova feature requests which are yet to be developed ? I am thinking of contributing to adding new features.