We’ve discussed whether we should look at creating a provider, but at the moment we can’t prioritise it above other projects.
That said, we do already have an ‘Octopus As Code’ module, OctopusDSC, which we also use in Octopus Cloud, and we do support and encourage Open Source contributions, so if a community effort came together around a Terraform Provider, we’d be very happy.
We also have a UserVoice site, which we use to prioritise future work, so with enough interest from our users, plans could change.