The Empire of Atlantium https://www.atlantium.org/
Basque Country (within Spain) The statue of autonomy of the Basque Country.
Pitcairn Islands https://www.government.pn/
Sealand https://sealandgov.org/en-au
Vatican City https://en.wikipedia.org/wiki/Vatican_City
Monaco https://www.mairie.mc/en
Hutt River Province website
https://www.principality-hutt-river.com/gov/PHR_Historic_Secession_Documents.htm