Discogs with about 1800 records. Invaluable when looking for records out of town/abroad, and checking it through the phone app. Works reasonably well, with a few known problems e.g. with Molchat Doma which is entered in Cyrillic letters in discogs (Молчат Дома) so is really hard to fine on app with roman letters.
Re barcode and catalog numbers, there are many records that have multiple version with same catalog number or barcode. This is where discogs shines. You can also search by barcode number and it will provide list of all the versions under same number.

