There are two main types of tectonic plates: oceanic plates and continental plates. Oceanic plates are made of denser rock and are found in the oceans. Continental plates are made of less dense rock and are found on the continents.

In addition to these two main types of plates, there are also three subclasses of tectonic plates:

* Active plates are those that are currently moving and interacting with each other. This includes plates that are colliding, spreading apart, or sliding past each other.

* Inactive plates are those that are not currently moving. This includes plates that are completely surrounded by other plates or that are moving very slowly.

* Relict plates are those that have been completely subducted and no longer exist.

The boundaries between tectonic plates are where most geological activity occurs. This includes earthquakes, volcanic eruptions, and mountain building.