From the Necron Model Range the only ones which are not plastic are:
Flayed ones
C'tan Shard of The Nightbringer
C'tan Shard of The Deceiver
This Cryptek
https://www.games-workshop.com/en-GB/Necron-Cryptek (the other newer one with the spider on the base is plastic)
This Lord
https://www.games-workshop.com/en-GB/Necron-Lord-with-Resurrection-Orb (the other generic lords are plastic)
The Destroyer upgrade packs (both lord and heavy)
ALL of the named lords - ergo all the unique characters
All of the above are in finecast. In addition all of the foregeworld models are resin (which isn't the same as finecast - its generally a lot better); or resin and plastic (for things like the aircraft which contain the plastic model and upgrade parts for it).
It looks like a lot, but honestly outside of the characters the vast majority of the necron range is plastic.