The figure on the left is generally referred to as a Fabuland figure, although I believe that the entire Fabuland line actually featured animals. There were a few basic sets released in the 80s that included human Fabuland-style figures. That one is probably from this fire engine:
Before the introduction of the Minifig in 1978, there was the Maxifig that you noted in your question:
The precursor to the modern minifig was added in 1975:
LEGO released a history of the minifig that you might find interesting.
In addition to the traditional minifig, you may also come across Technic figures which were around for a time.
There were also the Creator figures that were only around briefly in the early 2000s: