If you join Fly Delta Airlines, a Virtual Airline, they require you to have a Delta livery for certain aircraft (see below.).
New Hire - CRJ-200, CRJ-700, CRJ-900, Dash 8 Q400, EMB-145, ERJ-175, ERJ - 195, B717, A319, A320, A321, B737-700/800/900
Second Officer - Same as new Hire
Senior Second Officer - Same as new Hire and B757-200 B757-300 B767-300
First Officer - Same as Senior Second Officer
Senior First Officer - Same as Senior Second Officer and A300 B767-400 A330-200 A330-300 A340-300
Captain - Same as Senior First Officer and A340-600 B777-200 B777-300ER B787-9/10 A350
Senior Captain - Same as Captain and Concorde 737 MAX-7/8/9/10 ATR, B747-400/800 MD-88 MD-90
I will be bringing more liveries for each aircraft eventually. If you want a specific aircraft from the list above please reply and I will do my best to get it uploaded and reply fast!
https://drive.google.com/drive/folders/1tpm7gGTr1BtmNeKzgEXc3fD677f13xgp?usp=sharing
That link will take you to the place where you can find all liveries that I will make.