San Francisco Stitch Co used to have heart shaped, flag like, charms for several countries, but I didn't check to see if they were still available.
cheers, Meg
Only flag charm I found on their site currently, was the Irish flag with the St Patrick's items. Hopefully they will being back some of the others too. At least with them still in business, it likely would not be hard for them to add other flag charms back to their site. Could not hurt to send them a message. Good Luck!
Off hand I do not know of a site to lead you to. Sharing is against copyright and not allowed. If I find a site that sells the flags or find a free one I will come back and post a link for you. Maybe someone else knows of one.
Found this one
https://www.embroidery.com/Machin...