BIS, Bank for International Settlement, published a research report titled "Central bank cryptocurrencies", in which researchers created the below Money Flower to categorize all Money.
But if we broaden the definition of central bank to be any central authority that issues Money, Cryptos do belong to "Central Bank Issued".
As to "Universally accessible", Cryptos may have problems too when a place is out of electricity.
But I do like the Money flower very much because it gives you a clear picture of where all Money forms belong and you can tweak the flower according to your own understanding.
I personally still like precious metals best because they are truly universally accessible, accepted, peer to peer, not electronic, not issued by anyone(may be issued by God).
Full paper can be read at below link:
https://www.bis.org/publ/qtrpdf/r_qt1709f.htm