Above: you could lean an oversized piece on top of a dresser or credenza — no hanging required.
If a piece is big enough, you could even lean it on the floor, as in this dining space from BHG.
Or lean multiple smaller pieces next to each other in groups.
Or try this — a low shelf just above the floor, propped on some old magazines. I really like the way this turned out: it gives the art a little bit of presence and makes it look intentional.
A ladder makes a nice impromptu bookshelf — and a great place to hang art.