Label Flow can print code labels from various standards.
You can print 1D and 2D barcodes.
From an existing application, it can print code directly.
Morovia is a simple barcode generator website. You can even use Morovia for generating QR codes.
TECIT is a free online best barcode generating software. Using the free barcode maker, you can generate and use barcode for commercial purposes.
Cognex have a range of barcodes, which are linear codes, 2D codes, mobile tagging, EAN/UPC, ISBN codes, business cards, event barcodes, and Wi-Fi barcodes.