The country with a red, blue, and gray flag is the flag of the Republic of Crimea, a region within Ukraine that was annexed by Russia in 2014. The flag features horizontal stripes of red, blue, and gray. However, if you're referring to a national flag, there isn't a recognized sovereign nation with a flag that exactly fits that description.
Chile. It's in South America.
A country whose flag has the colours green, white and red
Their uniforms were gray. If needed...the Confederate flag had a red background with a blue X across it outlined in white. The uniforms of the Confederacy were gray. Their flag was red, white, and blue.
The flag with white and red stripes is the flag of Poland.
That is the flag of the Red Cross, not of a country. The flag of Switzerland has a red background with a white cross. The flag of Tonga has a red cross on a white field, the corner of a red flag.
Red, White and gray
Japan's flag is white with a red dot in the center.
Switzerland- the Red Cross flag is the reverse image.
The Ohio state flag features the colors red, white and blue. It was designed by John Eisemann and was officially adopted as the official state flag in 1902.
China's flag is red with five yellow stars.
Venezuela
The red-over-white flag of Indonesia becomes the white-over-red flag of Poland when turned upside-down.