Not all developed countries are phasing out 2G. Here in The Netherlands for example several major providers still support 2G and say that they will continue to support it for the coming years.
You could try and sell your phones online, but shipping to the nearest country that still has 2G may cost quite a bit and also has a footprint of course.
I'm not aware of any program that sends 2G phones collectively to other countries, but you could reuse (one of) the phones yourself as a watch/alarm clock. Your 2G phone may even be more energy efficient than a regular alarm clock.
If these reuse options don't work for you, consider donating the phones to a good cause that recycles them. Some good causes collect old and broken mobile phones because they get money for it from recyclers. I did a quick Google search and found one Australian organization called PhoneCycle. They will assess the value of your phone and send this money to a charity of your choice.