OTF is an open source alternative to Terraform Enterprise. Includes SSO, team management, agents, and no per-resource pricing.
Docs: https://docs.otf.ninja/
Looking for a TUI for terraform? Check out PUG.
Legal
OTF is in no way affiliated with Hashicorp. Terraform and Terraform Enterprise are trademarks of Hashicorp. Hashicorp have confirmed OTF is in compliance with their BSL license.