Microsoft has released set of ten themes for SharePoint.You can download it from here http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=0a87658f-20b8-4dcc-ad7a-09ad22641f3a#tm, but these are visual studio extensions for SharePoint.
If you are looking for a WSP for ten themes check out Daniel Browns blog. Here is the link to download the WSP http://www.danielbrown.id.au/Lists/Posts/Post.aspx?ID=256
Once you install the package, goto Central Admin–>Operations–>Manage Farm Features and activate all the themes. Even after doing this some themes won’t show up. The workaround is to deactivate the ones which are not showing up and activate them again. You should get all themes.
My experiences with SharePoint, IIS, Windows Servers 