The Qatar flag is very unusual and striking, and it's an easy one to colour in. You will need to find a maroon colouring pencil or crayon...
Qatar Flag Colouring Page
Here's a colouring flag of Oman to print for the kids. The central and left section is a bright red, while the crest stays white and the bottom section is green.
Here is a colouring page of the Bahrain flag, ready to be coloured in with its striking red and white design.