Forgive me if this topic has been covered already. i've searched the forum and I've had no luck (is the search broken?).

Primarily, I really need to stock up on 2* rainbow evo runes so I can upgrade some talismans. I've been on zero for quite a while and I've decided to head back to the cosmos to try my luck harvesting some materials. I've been spending some time going through Battlefield on Madness and haven't had much luck so far.

Any suggestions? Is there a guide out there that points out increased drop rates for different materials?