The Mana Bros. Cthulhu Pages is an Italian website (in English) which has lots of material for Call of Cthulhu, including a Delta Green campaign set in Vietnam and a guide to Turin and Italy during the 1920s.
It’s a well-written site, with excellent graphics and quotes.
One section of their site, Niteside Dreams, describes an alternate CoC setting that mixes Noir and modern Magic with the Mythos. As a reference for mundane magic, they point to a big Sandy Peterson article about Sorcery in Runequest (easily adaptable to CoC). That article is hosted on David Dunham’s site, which has an impressive collection of Glorantha material. Dunham is the creator of the Gloranthan computer game, King of Dragon Pass.