#16 the tabs are too far apart . i have now goten these in a few diffrent auction lots .
Odd... I can't think of anything else it could be.
#21 looks like the bottom half of a deep sea diver's helmet, probably the one found in set
3348.
#22 could be the top part of a vase. The one in set
3022 looks similar and comes in 2 separate pieces.
Is #18 a circular part with 3 legs, lying on its side?