Both Portals, obviously
Smash Bros Melee sticks in my mind, probably because it's the credits scene I saw the most
https://www.youtube.com/watch?v=rMvNpetkHtI
I quite liked it in W101 and Bayonetta that it gave some extra little gameplay scenes to go through.
https://www.youtube.com/watch?v=VedX3cuuPac