DigiVatLib, ( digital Vatican Library) allows you to explore a selection of digitized materials from their vast catalogue.
Source: J. P. Mauro, "Vatican Library makes 15,000 manuscripts available online for free," Aleteia, June 2, 2018, https://aleteia.org/2018/06/02/vatican-library-makes-15000-manuscripts-available-online-fo...
To learn more:
Here is the link for the website of the Biblioteca Digital del Patrimonio Iberoamericano, created with the collaboration of fourteen national libraries in Latin America. Be careful! It is absorbing.