1U4UN     Bir Tawil - not valid
4U1UN/B     Beacons are not valid
7U9NCD     Pirate

A7XGI     Pirate
C3PO     Pirate
CN8JJ     Pirate
CY9SPI     Pirate
D0B     Invalid callsign
D0NECK     Invalid callsign
D0Y     Invalid callsign
D1A     Invalid callsign
D1B     Invalid callsign
D1D     Invalid callsign
D1DNR     Invalid callsign
D1DPR     Invalid callsign
D1T     Invalid callsign
EP3FS     Pirate
EP3MS     Invalid callsign
EP4MRG     Pirate
ET3JA     Invalid callsign
EZ      No EZ callsigns are currently accepted
FK8IK/M     On Boat - not valid
FT5XV     Pirate
FT5ZM     Pirate
GJ0KE     Pirate
HS/VA7UR     Not authorized
JX2016A     Pirate
P5DX     Pirate - April
R55YG     Invalid Call
T00CW     Seborga - not valid
T00RM     Seborga - not valid
T31LP     Actually operating from a boat
TA7/YI1RZ     Pirate use of callsign
VP8DPC     Operating from a ship - Feb, Mar
YI1BGD     Pirate use of callsign by Hassan
YI1DJ     Pirate
YI1DX     Pirate
YI1H     Pirate
YI1HI     Pirate
YI1HR     Pirate  
YI1HRP     Pirate
YI1IRQ     Pirate use of callsign
YI1RZ     No longer in Iraq

http://www.dxmarathon.com/helpfulhints/2016/Invalidcallsigns2016.htm