I found out that "Rucker's Cavalry Brigade Flag" was captured on Dec 16th, 1864.

"In this engagement the 12th Tennessee Cavalry U. S. A. clashed with the 12th Tennessee Cavalry C. S. A. Captain Boyer, of the 12th, had a hand-to-hand fight with Colonel Rucker, then commanding a brigade. Each wrested the sabre of the other from his hand. One account says Captain Boyer then drew a pistol and shot Rucker in the arm. Another account says Rucker was shot by an unknown soldier standing near by. The flag of Rucker's Brigade was also captured."

http://www.tngenweb.org/civilwar/usacav/usa12cav.html

Usually I stick with captured Union flags, but that site is great. Found out the 28th Tenn captured the 9th Kentucky Infantry (USA) flag at Murfreesboro, Jan 2nd, 1863.

Brice's Cross Roads.
The 2nd Tenn Cav and 7th Tenn Cav captured:

"3 Stand of colors, 1 Artillery piece". Did not say which flags and who they belonged to.

Curious to the garrison of Athens, Alabama. Forrest on Sep 24th, 1864 captured the garrison. 820 Union prisoners. Sounds like some Union flags were captured...

Have a great weekend!

Shawn