NGC 6791 is an interesting open cluster in Lyra, containing thousands of stars, its one of the older clusters known at 8 billion years. Most clusters tend to disperse over the millennia due to gravitational influences. In addition the stars are metal rich that is to be expected for an old cluster. Old clusters tend to be metal poor in their composition as it usually takes several star birth, death cycles to build up metals. That makes it one of the most studied open clusters.
The bright reddish-orange star above and left of the cluster is U Lyr, a red giant carbon star.