Finding intelligent toys for kids is not easy. Add to your requirement eco-friendly materials and it can turn into a real challenge!
Major department stores offer aisles and aisles of options, but most of them are made of lousy expendable materials, expensive, and not educational.
I'm on a mission to find good options of eco-friendly and educational toys. I'll post more sources as they become available. In the meantime, check these websites, featuring eco-friendly toys by age, and category such as books, games, dolls, musical instruments, etc.