There are a huge variety of minifigs, the bricklink reference catalogue lists 2905! This makes my collection seem quite modest.
I think that minifigs can be split up into different sorts, a bit like bread. As a child, I would cycle to the local bakery and buy "one small white loaf". As I grew up the wonders of brown bread, granary, baguettes and speciality breads expanded my culinary horizons.
"Legoland old type", first appeared around 1975. I had some of these as a child.
Sliced Bread
The first "true minifigs" appeared around 1978. The best things since sliced bread, these had moveable arms and legs. We both had some minifigs from the classic space series
Speciality
Modern minifigs come in a huge variety of colours, and styles, from cowboys to vampires.
Baguettes
Modern lego minifigures also include non-standard sizes, from the diminutive Dobbie to the huge Hagrid.
