HashiCorp, which owns Terraform and administers the certification, publishes a free official study guide along with HashiCorp Developer documentation and tutorials mapped to the exam objectives. Since it's the source of the exam content, alignment is guaranteed, and the price — free — is hard to beat.
What HashiCorp's own materials don't provide is individualized readiness tracking. The study guide is a reference checklist, and the tutorials are organized in a fixed sequence, with no diagnostic upfront and no evolving prediction of your pass likelihood as you work through them.
Edureify's curriculum is built on the same HashiCorp documentation and exam objectives, but the Diagnostic identifies specifically which Terraform concepts — state management, modules, or workspaces — you're weakest on, and the roadmap keeps you there until your Readiness Score improves.