Yes, with the Tolino you can also buy from other booksellers. There are a good dozen suppliers of e-books that are immediately recognised by the Tolino and displayed directly. You can set this up if you wish when you use the Tolino for the first time.

I can't confirm whether Exlibris is one of them, because this provider is unfortunately rather expensive and extremely complicated with the access rights (Exlibris is 100% 'tied' to Adobe to prevent possible pirate copies, which is extremely customer-unfriendly in my opinion). Theoretically, however, it should work.

Perhaps there are members of our Digitec fan community who actually buy e-books from Exlibris and can report on current circumstances.