Old versions of the OS X Human Interface Guidelines
It wasn't easy, but I think I got all of them.

2006-10-03:

https://web.archive.org/web/20070520203932/http://developer.apple.com/documentation/UserExperience/Conceptual/OSXHIGuidelines/OSXHIGuidelines.pdf

2008-01-15:

https://web.archive.org/web/20080225084449/http://developer.apple.com/documentation/UserExperience/Conceptual/OSXHIGuidelines/OSXHIGuidelines.pdf

2008-06-09:

https://web.archive.org/web/20081222045913/http://developer.apple.com/documentation/UserExperience/Conceptual/AppleHIGuidelines/OSXHIGuidelines.pdf

2009-08-20:

https://web.archive.org/web/20110604173215/http://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/AppleHIGuidelines/OSXHIGuidelines.pdf

2012-07-23:

https://web.archive.org/web/20121004065110/https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/AppleHIGuidelines/OSXHIGuidelines.pdf

2013-10-22:

https://web.archive.org/web/20140603021344/https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/AppleHIGuidelines/OSXHIGuidelines.pdf