Needle clamp assemblies. The nose covers and lids from the Touch & Sews. They get broken off occasionally though not as commonly as Rocketeers.
Take a look at Ebay listings for an idea of what's commonly listed for sale too. That might give you some idea of what's worth keeping from your machines.
Hand wheels and clutch parts if they're in good shape. I have a couple machines with poor cosmetic condition hand wheels. I see plenty of machines of all makes with bad hand wheels.
Screws are commonly lost, it wouldn't hurt to save some from the outer covers.
If I keep going, I'll have you saving the whole machines.
It's actually not a bad way to keep the parts, that way you know where everything goes later.
What were your plans for the parts? I think CD was looking for a zigzag needle plate for a 400 series machine. 600 series Touch & Sews use the same plate.
Rodney