I'd like to see a Railroad J83 in NBR livery(NBR Holmes 795 Class (Power Class D) - the tooling is many years old I don't think there has ever been a model issued in the original NBR liveries despite the availability of coaches and wagons.
J83's were used with both freight trains, occasional passenger trains and as station pilots.
the possible liveries would be as built, the Holmes scheme of Dark Ochre / Bronze / Olive (I've never seen anyone be able to name it) or yellow lined black or finally plain black around 1915. There is also the possibility to mix the roundels and the large control numbers on most of these liveries. (this is covered in some detail in the NBR Study Group Journal 142 from 2021).