NPC's only fly Vipers, DBX, ICouriers and Anacondas.

And every once in a blue moon a Clean FDL.
From what I've seen in RES-s, pirates there fly:
Sideys
Eagles
iEagles
Adders
Viper III-s
Viper IV-s
Cobra III-s
Cobra IV-s
Couriers
DBS-s
DBX-s
Asp Scouts
AspX-s
Federal Brickships (really popular mediums for them!)
FDL-s (seem to be more common in haz RES-s)
Clippers (really popular large pirate ships!)
Anacondas
CNB-s add to the mix:
Alliance C-ships
Krait MKII-s
Krait Phantoms
Mambas
"Massacre X facton deserters" missions also offer:
T6-s
Keelbacks
T7-s
T10-s
Corvettes
Cutters
But only if you pull mission ships from SC. Mission signal sources are bugged IME, anyway. Bonus: these mission targets are considered cargo ships, so drop mechanical and conductive engineering materials which the normal pirate ships don't.
As for the topic at hand, pirate PII-s at haz RES-s, CNB-s and as mission targets would be cool.