What do you think about eco-friendly toys for kids? Maybe do you create some of them on your own? May they be attractive for children in our times, when it is important to have the newest smartphone model?
Do you know some less / zero waste toys which I can buy for a little boy as a birthday present? I was thinking about some wooden train, board game or old set Lego - I heard that brand gives a possibility to rebuild old set (like sports car from Lego Technics) with Green Instruction lego tutorials - he’s 7-years old and he likes to construct and demolish (mostly demolish) 
Do you know different brands and activities like this? I’m interested in educational and functional toys mostly - enough of computer games etc.
Recently my nephews/kids have been having a lot of fun with the wooden train sets. Now I got mine from a thrift store. But I do know that they have 3d models for printing them on thingiverse and if you have a little woodworking skill and a router I had a friend make them himself. I might need to reach out to him and see if I can get images of the pattern jigs he used to make them. Then you can build/paint your own trains and if you really are itching you can make a battery powered train that runs on the rails.
Also as an avid board gamer I will always recommend them. I would suggest “Forbidden Island” as a good starting one. It’s completely co-operative so its you against the game and the rules are pretty easy to understand. Really anything made by HABA is a game I would recommend looking at. Plus they are still fun for adults most of the time.