Yes, Google Docs does have cover letter templates.
They are easily accessed by following these steps:
- Log in to your Google account
- Click on the Apps icon in the upper right corner
- Click on Docs
- Select Template Gallery toward the upper right corner
- Navigate to Letters and choose a template you like
RecruitableHub provides a collection of exclusive cover letter templates that you can access here: https://recruitablehub.com/get-started/