At least one is a build started here for a postponed Expo-themed kit build, the good old Airfix 737-200, the others are a Minicraft 737-300 and a Revell 737-800 converted to a -700/BBJ
So here they are as they stand now

And the decals/colours they will eventually wear.

I think I have managed to find all the remaining parts for each kit.
Hopefully, I can keep this thread humming along and at an acceptable pace