We have four sets of Serbia bookmarks featuring the country's flag. Two are in colour, two in black and white for the kids to colour in.
Our Turkey bookmarks would also make handy classroom labels and come in 4 versions; with or without country name, colour or black and white.
We have four variations of this St David's flag bookmark printable including 2 in colour and 2 in black in white for the kids to colour in. The blank bookmarks make useful labels, too.