Light Objects
Jar of eyeballs
A dictionary
A rabid badger
A fish


Heavy Objects
A coffin
A Blue Police Box
A ship's wheel (for steering)
A Barrel of fish

Thanks for the response: 12 items each!
Here's the rest of mine (I checked those above, I did not check these, so if it's a repeat--sorry!)

Light:
4. club
5. filing cabinet
6. newspaper rack (display/stand/dispenser/whatchamacallit)
7. cream pie
8. turnstile
9. potted plant
10. framed picture
11. puppet on strings
12. boardgame/chessboard

Heavy
4. cement mixer truck
5. tank
6. cannon
7. pool table
8. barrel of monkeys
9. billboard
10. subway car
11. uprooted tree
12. throne