Well, for me the main uber unis I here about are the English ones first:
Oxford and Cambridge. Then Harvard, then here and there during university classes I heard about Princeton, MIT. I know about Yale but hardly mentioned and I know of ucla only because I have a relative who did a year exchange there. And that's it.
I think it is more reasonable to be buy sports team gear though, being that the sports teams have provided entertainment or a spectacle for people to enjoy. Buying their gear is to provide support for the teams to continue to entertain you.
However I find nothing of the sort of return for your investment into a University brand.