Cakebread & Walton has 2 games with a strong Mythos/Cthulhu element.Dark Streets
is a stand alone OpenQuest inspired d100 system. It's London 1749 and the idea is you are part of the police force dealing with Mythos and mondaine issues.Clockwork & Cthulhu
aims at adding a Mythos element to Clockwork & Chivalry. It' set in 17th century England. It'seems ot stand alone, but there is a free Renaissance d100 system (Cakebread & Walton core D100 system, an OpenQuest variant), if you do not wish to get the Clockwork & Chivalry corebook.