DHL Leipzig
Lufthansa CityLine/Eurowings (DLR used to do tests in English until very recently)
Voltea
Air Contractors Eire
Aer Lingus
RYR
EZY
etc, etc......
Had interview with SAS/Cimber in July 2016 (before they were taken over by Cityjet) - one of the questions was about how Brexit might affect employment terms.....
Even US-EU/UK Open Skies agreement likely to be affected:
Brexit could lead to doors closing on Open Skies | ATW Editor's Blog