Polymaker Panchroma Gradient Satin Rainbow 3D Printer PLA Filament, Multicolor 3D Printing PLA Filament, 1kg Spool (2.2lbs)

The most engineering-minded consumer brand in this space. Polylite is their everyday PLA, PolyMax adds impact resistance, and PolyWood nails the timber look. They publish data sheets and actually explain what's in their formulations.