NCL-IST: Turkish
NCL-STN/LCY: Ryanair/Cityjet
NCL-FRA: bmi regional
NCL-GDN, WAW, BUD, RIX: Wizzair
NCL-HAM: Eurowings
NCL-MXP, MUC, KEF, RAK, JMK: easyjet
NCL-Cape Verde, PVR, PUJ: Thomson
NCL-MAD: Vueling/Iberia Express
NCL-YYZ: Westjet
Plus a few more one off charters, maybe TCX or VS to Las Vegas or something like that, I'm sure they could fill 1 A330 a year, Ryanair base would be great if they could boost already busy markets like PMI, TFS, FAO, ACE and maybe introduce a few more unserved ones in Spain, Italy etc.
Someone to Norway would also be up there in my wish list for NCL as well as a return of Venice, Berlin and maybe a few more, that's probably easyjet/Ryanair territory