Although the 737 series have been remodeled there is some aircraft that are missing from the family of course I will include all the veriants included the gravel kit for the 737-200 Update: changed 737-200 and 737-300/500 into a better quality picture.
737-200 (without gravel kit)
737-200 (with gravel kit)
737-200F
737-300/500
737-300F
737-700
737-900
737-Max9
Of course the 737-200 is a historic aircraft which will cost quite a bit.
What do you guys think