Trim sheet
A single texture holding strips of reusable detail — moldings, panels, pipes, bolts — that many 3D models map onto instead of each getting a unique texture.
Artists map several models onto the same sheet: a wall, a door frame and a pillar can all pull their trims and seams from one texture by UV-mapping only onto the right strip. It saves memory, keeps the style consistent, and lets a model be built in minutes rather than packing every surface into its own atlas.
The method spread with modular environment design in the mid-2010s and is now standard in large productions. A trim sheet is often combined with detail textures and decals for unique touches, so the repetition never becomes obvious.