Gasses, liquids and crystalline solids.
The three ordinary states of matter are gasses, liquids and crystalline solids.
However, there are other less-common states of matter. Here are a few examples:
glass – an amorphous solid material that has a molecular structure somewhat like a liquid (no long-range order) but is cool enough that the atoms or molecules are effectively frozen into place.
colloid – a dispersed mixture of two immiscible substances. Milk is a common example, where milk fat particles are suspended in water.
plasma – a collection of ionized particles similar to a gas
liquid crystal – a collection of molecules that can flow like an ordinary liquid, but where the molecules may orient themselves or be oriented in an external electric field.
See also the answer to the following question on this website: