Modeled after the Rogue Fitness bumper plates. Printed in red, blue, yellow, green, and black corresponding to the correct weight. Text in pictures added in Fusion 360.

If you want to embed magnets:

Print this model, honeycomb infill at 20%, pause at 43%, and press fit 5x3 magnets in the infill. Works really well. I personally use four magnets in each print, but I have tested it with three and it works fine.

EDIT: If you are using the X1 Carbon, 20% infill is too much, will have to go 10-15%.