How to Delete the Default parameter groups and Option groups if there is no RDS being used.

Hi,

Please note, Amazon RDS provides an empty option group for each new DB instance. You can't modify or delete this default option group, but any new option group that you create derives its settings from the default option group [1].

Furthermore, you can modify parameter values in a customer-created DB parameter group; you can't change the parameter values in a default DB parameter group. Changes to parameters in a customer-created DB parameter group are applied to all DB instances that are associated with the DB parameter group[2].

Reference

[1] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_WorkingWithOptionGroups.html#Overview.OptionGroups : Working with option groups - Option groups overview

[2] https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_WorkingWithDBInstanceParamGroups.html#USER_WorkingWithParamGroups.Modifying : Working with DB parameter groups in a DB instance - Modifying parameters in a DB parameter group

Hope it helps and if it does, I would appreciate if answer can be accepted so that community can benefit for clarity when searching for similar enquiries in repost/aws guide.

Thank you!