Polymaker Fiberon PETG-RCF Filament Black 3kg, Recycled Carbon Fiber Reinforced PETG 3D Printing Filament Ideal for Drone and Automotive Products

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.