FAR 18's Kaserne is still there, although partly collapsed. It was a Soviet barracks, I believe. The nearby GR 12 barracks is now a university.
FAR 25's Kaserne was destroyed during World War II, as was almost the entire complex of the Großherzoglich Hessische Division on the southwest side of Darmstadt. Parts, including I believe some of Train-Abteilung Nr. 18's barracks, were used by the US Army. The Kasernes of DR 23 and DR 24 are almost entirely gone, as is most of that of LGIR 115.
For FAR 28, the wings of the Kaserne buildings are there, but the center parts of both barracks are gone, turning two long buildings into four shorter ones. Elsewhere in Bautzen, IR 103's complex is mostly gone, while HR 20's is mostly still there.
Here is a Google Earth street-level view of the Offizier-Kasino in Nysa: