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Ok, so we have Single-Palette Town, but I'm not sure if this covers examples where it's not supposed to be literal and is a stylistic choice (i.e. a music video set in a White Void Room where all the musicians wear white and have white hair & faces, or a comic where everything is filled with pink instead of white).
"It's just a show; I should really just relax"
Color Motif, Mood Lighting, and/or Color Wash and their related tropes. Cold, Unnaturally Blue Lighting was a trend for a while (and still is, to a lesser extent), Synchronicity just started a draft for Warm Country, Warm Filter
on TLP. Red Filter of Doom for everything being red during scenes of tension/violence/horror/etc. Coordinated Clothes for matching outfits.
Do we have a trope for where everything in a scene or setting is only one (usually a bright) color? Deliberately Monochrome is for black and white/greyscale only I believe. This would be for everything is red, for example.