[@mmc_jake]

Plywood could be an option here. Could be cut with a jigsaw or a laser or CNC if that is available. (Laser would provide some nice customization options). That would be relatively easy to glue up and finish in a way that is easy to clean.

Acrylic is another commonly used material, and probably the easiest to clean. Downside being it is harder to cut cleanly without access to a laser/waterjet and is far more expensive. Making the lip around the edge in pieces could cut down on the material required.