When the 'Remove' button is clicked on any OOTB offering folder, is removed from Catalog's UI, but this is just a 'soft delete', which means that the information remains at MDB level, but not displayed on Offerings section.
For example, if the folder "IT Support Service" is deleted from UI, offerings like "Report an Issue" or "Reset User Password" won't be available. But going to the MDB and run a SELECT against "usm_offering" table, both offerings will be listed.
Since the remove was done at folder level, the first thing is to identify the whole path of the offering. If we take "Report and Issue" offering as example, we will see the path is something as follow:
Which corresponds to: "BU -> IT Support Services -> Service Management -> Report an Issue "
Now, we need to check the 'parent_id' of each. Since the removal was done on "IT Support Service" folder, its 'parent_id' will "-2".
In order to restore it, we need to set the right value for its parent, which is BU's "offering_id", on this example corresponds to "10001", which can be set using the following query:
SET parent_id = 10001
WHERE offering_id = 10082
After this, and restarting Catalog's service, the OOTB offerings will be available again.