SUNLU TPU-Silk 3D Printer Filament, 98A TPU, Glossy Silk Surface, Flexible, 1kg (2.2lbs), Black

Well-known as much for their S1/S2 filament dryers as for the filament itself. The material catalog — PLA, PETG, ABS, TPU, silk — is broad and frequently discounted on Amazon. Solid all-around option.