What prompted the question, was the idoicyncratic designs of the standards of the 8th NY and 13th NY Cav regiments which can be viewed at the link for NY flags. There is also a photo of the officers of the 13th NY with two flags (both probably with blue fields) on p. 173 of Vol. 4 of the "Photographic History of the Civil War."
The link to the Illinois cavalry flags shows that westerm regiments very often carried the Stars and Stripes. However the standard of the 4th Ill Cav is also far from the regulation stantard.
Note in all three the use of clouds.