How does one change the date format to 'YYYY-DDD' e.g. 2020-001 for the Data Grid Data output in Toad for Oracle?
The option for a free-form format model doesn't seem to exist in View|Options|Data Grids>Data>Display>Date format:
You're right, there's no option for that. You'll have to use TO_CHAR in your query to get that format.
Or submit an enhancement request to allow users to enter a date mask. Especially useful if user is seeing the data without running a query (e.g. in the RHS Data tab of the Schema Browser for a table.)