To apply a single resource
terraform apply -target=<resource_type>.<local_name>
eg:
terraform apply -target=google_sql_database_instance.instance
To get a single resource from the state file
terraform state show '<resource_type>.<local_name>'
eg:
terraform state show 'kubernetes_secret.cloudsqlproxy-SA'
To delete a single resource from the state file
terraform state rm '<resource_type>.<local_name>'
eg:
terraform state rm 'kubernetes_secret.cloudsqlproxy-SA'