Saved Search That Pulla all Opportunities Without an Associated Quote

1. Navigate to Lists > Search > Saved Searches > New > Type = Opportunity.
2. Create the Search.
Criteria:
    Document Status = is not Issued Estimate
    Estimate fields...: Document Number = is Empty

Note: The Saved Search excludes any Opportunities with Issued Estimate status (the Issued Estimate status is only being set when an Estimate is generated from the Opportunity). This also checks the Estimate sublist from the Opportunity and makes sure it is Empty, if there is an Estimate record, then it automatically excludes it from the list.