I use some small display cases from arts & craft stores. The football display cases are a good size for displaying assorted figures, they have a mirror for the back panel, and it's easy to make little riser inserts to put in them, to allow viewing the figures at the back.
I also have some long-range projects to increase display space. I bought a china cabinet at a yard sale, it stands about 5' high, and has a glass front and sides. It's a nice reddish or copper-colored wood, and I'm refinishing/refurbishing it, to use for display.
Another display cabinet is an old microscope case, about 20" square and about 4" deep. The front of the case is its door or lid, consisting of a narrow frame holding a large pane of glass, and hinged at the bottom. It still had a lock and key, and a little celluloid plate with the maker's name and address. I refinished it and added a light, and a glass shelf about halfway between the top and bottom, and some hardware to hang it on the wall.
And at Christmas, I set up a Putz under the tree, with sets of figures. Some years, it's the Kaiser taking the salute at a Christmas parade of the Alexander grenadiers (Guard Corps, Stadden, Rose figures, among others), or Washington and some Continentals, or the Reeves French line infantry band. This year, it was civilian figures, musicians from the 18th century, in a Christmas concert (Mozart on piano).
But a lot of stuff is still in boxes.....
Prosit!
Brad