I don't have any suggestions for strong plasticish sturdy ones since I have the same problem with Sawyer. I usually use the kong Frisbee (red), its floppy so it doesn't fly the best but its lasted really well. It works pretty well if you toss it more on its side especially for shorter distances. It goes pretty far if you just throw for distance (not like a plastic one though) and doesn't have great directionality, but for generally Frisbee play/general play its nice to have. And since its soft you can use it indoors too (really just less off a chance of breaking something vrs a plastic Frisbee lol)