The six original Monopoly pieces - early 1930's:

1. Top hat

2. Thimble

3. Iron

4. Boot

5. Battleship

6. Cannon 

Pieces added in 1935-1936:

Race car

Purse

Rocking horse

Lantern

Pieces added in 1950's:

Scottie dog

Wheelbarrow

Horse and rider

Pieces added 1999-2016:

Sack of money

Cat

Pieces added in 2017:

T-Rex

Rubber ducky

Penguin