The barcode package is:
and provides support for basically all 1d barcodes.
In fact, the default barcode type is code128auto, afaik. You can add a barcode generator by going to setup>customize on a page (typically the ‘item’ page) and either making a new section, or adding to the existing barcode section, and inserting a new field with type ‘barcode’. Hit the checkbox for ‘show in list view’ and it’s on the page now- just pop the barcode right into the top line and click the (invisible- really just anywhere right of the image box) go button.
As far as populating existing values into the generator automatically for printing/quality of life… someone else can pop in or I’ll get back to you; I still haven’t gotten around to perfecting my ‘pulling values from child table’ skills yet and have just been using the Libre Barcode 39 font with *'s for the start/stop.
Also be sure to check out: