You would think that iTunes would have a separate category for Music Video media, but no, Music Videos live with Music.
To make them a bit easier to find, Apple give you Music Videos Smart Playlist. For some reason mine got lost.
Here's how to re-create:
- Choose File > New Smart Playlist.
- Set rule to Video Kind is Music Video and click OK.
- A new Smart Playlist will appear in the source list.
- Rename the playlist to "Music Videos."