alt Hacker NewsNice, but quite the short list (iTunes, Safari would be nice).
A lot of experimentation went on with the iTunes icon in particular (and iTunes in general). It was the UI playground for new ideas before they would release in the next OS version.
https://www.versionmuseum.com/history-of/itunes-app
As you can see the icon changed multiple times even within the same year or same OS version.
Most people think of the brushed metal, but I've always liked the iTunes 10 dalliance with vertical window controls as a good example of this.