This is an idea ive come up with that is similar to the most recent update. (777 rework and 787 added). My idea is that the 737-700/800/900 can be reworked. Along with the 737MAX-7/8/9 being added. Add Split Scimitar winglets to some of the 737NGs.
Here are the liveries that i think should be added:
737-7MAX
Southwest
Canada Jetlines
Westjet
IF Livery
737-8MAX
Aeromexico
Alaska
American
Cayman Airways
FlyDubai
GOL
NOK Air
Norwegian Air Shuttle
SilkAir
Southwest
TUI
Turkish
VietJet
737-9MAX
Air Canada
United
Lion Air
Alaska
Icelandair
Avolon
Turkish