The Turkmenistan flag isn't going to be the easiest one to colour in! There is lots of detail in the "carpet" stripe to keep the kids busy...
Turkmenistan 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.