I might suggest a few from the Slavic side of things: - vozhd (or Cyrillically, [вождь]), which is what adoring fans called Stalin; like Führer, it means "leader", but unlike the German word, it really is reserved for the Great Leader. - vojvoda or vojevoda or voyevoda (or more Englishy, voivode), the Slavic "duke" (lit., "war-leader" or "warlord") and the origin of the toponym Vojvodina. – vladika, the title of the Prince-Bishop of the Principality of Montenegro. – you have tsar, but what about the tsarina (I'm assuming you are eschewing the unchewable cz- spellings).
And a couple obvious ones from across the Adriatic that seem to have escaped: il Duce (last seen in Salò) and the doge, in the company of Mrs. Doge, a.k.a. the dogaress or in Venetian, dogaressa, both fleeing incognito in a gondola.
I've culled some from Wiki's list of royal titles (my 2nd link): Khatun (a female Khan), Aryamehr ("light of the Aryans"), Princeps (the official title of a Roman emperor), Bretwalda (an obscure Anglo-Saxon leadership title), and Basileus (a title for a Byzantine emperor).
LOL Kahuna, I don't know why but this is a new favorite word of mine. Maybe i'm getting tired. But on wikipedia i found out there's forty different types of kahuna listed in the book, 'Tales from the Night Rainbow'. Night Rainbow. I'm adding that right away, I have never seen a Night Rainbow, have you?
Taoiseach is an Irish word, originally meaning "leader" or "chieftain". Now mainly used to refer to Ireland's prime minister; useful in alliterative phrases such as the "teflon taoiseach".
The second-in-command, or deputy prime minister, is referred to as the tánaiste. In history the tánaiste was the heir of the chief (taoiseach).
Wow, neat word mollydot! Is it Gaelic? I could check around here (Scotland) and see if they have the same thing. I hope you find the yarn shop soon! Spin-doctors might think they lead public opinion but I'm agin'it. Godfather is closer in the Hollywood sense but the traditional meaning is not one of absolute authority. Even the Italian equivalent padrone might instill fear in Sicily but it's just run-of-the-mill owner elsewhere.
Re yarn shop: It's not exactly a who, and I missed the list description about leaders, so it doesn't work at all for your list. But it's somewhere I'd like to be taken to :-)
Here's a better one: Taoiseach, an Irish word. Current meaning is prime minister, literal meaning is leader.
I think Guru is a kind of leader type although the word literally means teacher. Cos I looked up Lama, which have the same meaning. And I think a Lama can be considered a spiritual leader (as well as a teacher) to quite a few people.
From Wiki: Lama (Tibetan: བླ་མ་; Wylie: bla-ma) is a title for a Tibetan religious teacher. The name is similar to the Sanskrit term 'guru' (see Tibetan Buddhism and Bön). The title can be used as an honorific title conferred on a monk, nun or (in the Nyingma, Kagyu and Sakya schools) advanced tantric practitioner to designate a level of spiritual attainment and authority to teach, or may be part of a title such as Dalai Lama or Panchen Lama applied to a lineage of reincarnate lamas (Tulkus).