I would consider a rechargeable toy environmentally friendly. I would consider a solar powered toy even more so. I know that the number one issue with toy recycling is that the manufacturing process is not approved for, and does not use, the coded material recycling stamps. No toy without a material recycle stamp is recycled (to the best of my knowledge).
Glass and silicone are eco-friendly materials. Toys that are made of PVC plastics aren't "green" because of the toxins released during their manufacture and disposal. They're also the ones that contain phthalates, which I'm sure most of us know are not good for our bodies.