3D modelling that features very few polygons. Common in older and handheld game consoles such as the original PlayStation and Nintendo DS due to hardware limitations, some artists intentionally create works in this style as a homage to games from those systems.
Can overlap with pixel art due to the low-res textures applied to the models for authenticity.
On aibooru this tag applies to both 3D models and illustrations mimicking the style. To see 3D models only search low_poly 3d.