I know of precisely zero such companies, and I can't imagine how such a company would even have customers in the first place when Terraform already has a $0 pricetag.
I could maybe understand this for Consul or Vault, since those are actual hostable services that could probably be resold - but I don't know of anyone reselling those, either.
Dozens of them out there
I wonder with great interest which one of these got hashicorp worries about their wallet enough to make this move. Could it be env0 raising 42M earlier this year?
I wouldn't call them a competitor by any stretch; more like a partner. A Terragrunt codebase just wraps Terraform, with the same exact backends (including Hashicorp's SaaS offerings) and the same exact providers and everything.
I could maybe understand this for Consul or Vault, since those are actual hostable services that could probably be resold - but I don't know of anyone reselling those, either.