Keurig have publicly stated they are switching to using fully recyclable materials by 2020 (I have no idea why it will take them five years to implement something most companies have been doing for decades, but that's beside the point). You can see more at their Web site. You can also get Keurig-compatible (although not "approved") pods that do not have the outer plastic. They are just an upper ring, a foil cover and a filter with grounds dangling loose. While some of these make great coffee, I am told they go stle rather quickly if you don't have a tightly sealed container in which to store them.
Flavia/Alterra have their own recycling program. I don't know about home-use situations, but at least for managed, corporate-use programs, their single-serve packets can be recycled using the packet-disposal boxes they provide.
I can't speak to other single-serve manufacturers.