Each of the d orbitals would fill one electron at a time, as did the p orbitals, and then pairing would commence until the electron structure of n=3 was complete.

In addition to the s, p and d orbitals, there are also "f orbitals" with even more foolish shapes. They only exist in the ground state for elements with atomic numbers greater than 58 and we don't need to say too much more about them.

Summary Table