Seamless looping flag waving

I want to create a seamslessly looping animation of a flag. I haven’t used Blender in a while, so I must familiarize myself it again. I figure the flag can be a plane. I’d like to be able to switch the texture of the flag to create different flag animations. I don’t know what soft body simulation scenario is best. Would keyframes be the best way to go?

Any help is greatly appreciated.