mary and mac design studio compiled a list of 100 university libraries around the world that anyone can access. The list contains brief annotations do help you decide what to look at first.
The list of digital libraries includes big names like Harvard and Yale. The list also includes and medical libraries and libraries from which you can read texts and complete books.
I suggest you bookmark or save the library links you want in some way other than just bookmarking the blog page. The blog hasn’t been updated since the list was published in 2009.