Here's a Kuwaiti flag to colour in. You will need the typical Arab colours of red, green and black, and the central portion is left white. I think the flag has an almost 3D effect!
Kuwait 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.