It's certainly going to change, and once the Alpha Phase 4 is out I am going to check out some known Horizon farming planets to see what has changed, but at the moment I haven't seen bio with mats attached so that may end altogether, I have seen people gathering mats from wrecks so for Odyssey players that may be a major new source of mats, I will let you know what changes for known mat farming sites so all you have to do is wait a few days or a week, I expect phase 4 before not to long!
I'm very interested in what you find out there! As phase 4 is imminent, please do post your findings!
With (admittedly a lot of) luck, oversights like Selenium farming will be addressed in EDO. Fixing some of the impossible to find HGE materials would be welcome too ( you know which ones). But of course, that makes it all too 'easy' doesn't it.
Personally, I'm farming before EDO launches... "A bird in the hand..." FDev has a history of nerfing such things.
My hunch is that Dav's Hope et al will be nerfed.
Sites like Jameson's crash site will be nerfed.