There are twelve more or less 'confirmed' supervolcanos worldwide: four in the lower 48 (WY, CA, OR, NM); one in Alaska; two in Japan; and one each in Indonesia, Italy, New Zealand, Australia, and Ecuador. There's also evidence of possible supervolcanos beneath Guatemala, Vanuatu (in the South Pacific), the Philippines, Papua New Guinea, and under Loch Ness in Scotland.
I'm aware of the Supervolcano candidates in all the other areas you list, but the only reference to a Supervolcano under Loch Ness on the internet comes from a couple unsourced assertions on worthless nutty Apocalyptikook sites; can you provide a legitimate source for that assertion?
Interestingly nobody has actually defined a supervolcano or attempted to rigorously list them yet; there is a paper coming out the Bulletin of Volcanology soon that seems like it will do so, though.