This can be accomplished by running an Accounts report with a Cross Filter. The Cross Filters will permit you to include a sub-scope within an Accounts report to narrow the results to only those Accounts without Contacts.
  1. Navigate to Reports and click New Report.
  2. Select the Report Type Accounts & Contacts > Accounts
  3. On your Accounts report, click Customize to enter the Report Builder
  4. Click on the "Add" Multi-Button and select "Cross Filters." In the Cross Filter section now displayed, select Accounts without Contacts
  5. Configure the report to show All accounts/All Time
  6. Run the report
If you're planning to remove these Acccount records and would like more information, please see this article: Is it ok to mass remove household accounts with no contacts in Luminate CRM? (BB747165).