I always find it fascinating about how everything could've happened with intellectual development in reaction to Industrial Revolution and the rise of Capitalism and Western Imperialism, and frankly it's always been fun for me imagining a Cold War situation with alternative ideologies on the play, or imagining how socialism and/or state nationalism could've evolved the alternative way and change the world (Like in EdT's "Fight and Be Right" with "Soviet" British syndicalism). Or, like what maverick has done recently at the very least, keep an OTL one sticking and then see how things go. There are lots to play with. Narodism (where OTL communism is basically this plus marxism) or Menshevism could've taken hold in Russia. Pan-Islamism could've had its chance had Ottomans retained their pre-1878 strength/Islamic modernism could've rolled with surviving Ottoman Caliphate. Et cetera et cetera.
What kind of an alternative ideology would you like to see ? And which country which intellectual brewry would you add-this-part-take-that-one to get it ?