There are no tectonic plates made entirely of oceanic crust. All tectonic plates are comprised of both oceanic and continental crust, with one usually dominating the other.

Here's why:

* Plate Boundaries: Plate boundaries, where tectonic plates interact, occur both on land and in the ocean.

* Continental Crust is Thicker: Continental crust is thicker and less dense than oceanic crust. It's also older, having formed earlier in Earth's history.

* Oceanic Crust is Constantly Renewed: Oceanic crust is constantly being created at mid-ocean ridges and subducted at convergent plate boundaries. This means it's younger and thinner compared to continental crust.

Therefore, while a plate might be primarily made of oceanic crust, it will always have some continental crust within it due to the dynamic processes involved in plate tectonics.