I’m logged into ponoko, here’s their list of materials. Any numbers listed after a material are the thicknesses offered in mm. Only listing them for the materials people might use as a plate. I do not recommend them for metal, their prices are prohibitive. A basic 60% plate was quoted at around 200$. Their acrylic selection is wonderful though.
Fabric
Wool Felt
Ultrasuede
Synthetic Felt
Leather
Leather (Vege Tanned)
Upholstery Leather
Metal
Brass - 0.8mm Thickness
Copper - 0.8mm Thickness
Stainless Steel - 0.4, 0.8mm Thickness
Paper
Cardstock
Plastic
Delrin - 0.8,1.5,2.3,3.2,4.9mm Thickness
Acrylic - 1.5, 2.0, 3.0, 4.5, 5.6, 9.0 (varies based on color)
PETG
Styrene
Polarizing Film
Laserable Magnet
Polyurethane Foam
Rubber
Silicone
Wood
MDF
Painted MDF
Veneer MDF
Premium Veneer MDF
Melamine Finished MDF
Printed MDF
Coated MDF
Peel & Stick Veneer
Taskboard
Hardboard
Bamboo
Cork
Plywood
Cardboard
Corrugated Cardboard
Cardboard
Matboard
Coasterboard