NOW under my 2 months observation, I can confidently tell you guys that drop table is 100% different between each filament.
dark filament:
will drop all drop all astronautic and Zero-Point Condensate
electrical filament :
will drop mostly engineering and small chance drop astronautic mutaplasmids and Crystalline Isogen-10
EXOTIC :
drop all stasis webifier and warp disruption mutaplasmid and Crystalline Isogen-10
fire filament :
will drop all armor mutaplasmids and Zero-Point Condensate
gamma :
drop all shield one and Crystalline Isogen-10
CCP changed it but did’t public to us, so I am not sure if it will be changed in the future