A set from the original System of play in 1950
A train from 1966, which was the launch of the trains line
A set from the 1970s, depicting a ship from the famous and very popular "Space" line
Here is a Lego Duplo duck toy, which was aimed specifically at babies. It was safe to chew, and could be built on using other Duplo bricks
This is the "Tie Fighter Collection" from the 1990s in which Lego Star Wars was launched.
This is a set in the popular "Bionicle" theme from 2001, which was a combination of action figures that kept the play-like quality of mini figures.
Here is a set released in 2014 under the Creator sub theme "Modular Buildings". These buildings are highly detailed and use advanced techniques and pieces to create the buildings.