Just found this list on Wayland Games, havent seen it anywhere else yet, figured I'd share it :) enjoy!
Imotekh the Stormlord - Finecast - £10.50
Trazyn, the Infinite- Finecast - £10.50
Necron Overlord - Finecast - £10.50
Necron Doomsday/Ghost Barge - £31.00
Necron Flayed Ones - plastic - £20.50
Necron Immortals - plastic - £20.50
Necron Triarch Praetorians - plastic - £20.50
Necron Deathmarks - £20.50
Necron Lychguard - £20.50
Necron Catacomb Command/Annihilation Barge - multi-part plastic - £20.50
The Barge, Deathmarks and Lychguard have no mention of the material.
I'm not sure how much salt is required, since these products are actually up for order now, but take some anyway, just in case ;-) Thanks for reading!