OK, some of these may be a bit too kitschy for adults (and others are outright designed for kids), but there is something to be said for reflective surfaces that make a space feel larger and play on surrounding color schemes in natural ways.
This is an old trick in stores and restaurants, but cheap to implement via wall decals in small homes and rooms as well. Manufacturers have long realized that many homeowners would rather apply a removable wall stickers than paint (particularly since the former can accomplish mirrored, frosted, matte and glossy effects more efficiently).
Acte Deco is one such company, carrying a variety of inexpensive decorative solutions that are easy to install (and remove as well). While the rippled reflections are not fully mirror-like in effect, they operate on our optics to make spaces feel larger than they are.
Some are shaped like trees and other sizable-area objects, presenting greater surface area to the eye – others are smaller, more abstract and/or divided to essentially add lighting effects via strips and sections of reflectivity.?Circles, gears and flowers could fit in living rooms or common areas, while cartoonish trains, planes and helicopters are, of course, suited to play spaces and other children-oriented zones.