One that hasn't really been done in much detail since all the way back in the Before Times with A Giant Sucking Sound no less, is swing the Algerian Civil War the other way, which could not only (as in that TL) produce waves of attacks on Europe much sooner than the IS approach and in particular a major French reaction, but potentially spread to Libya in particular and then you've got a large chunk of the Maghreb "down" in internecine warfare with spillover towards Egypt, Morocco, down into the Sahel (earlier iterations of Sahel sovereignty movements glomming on to Islamic radicalism as with Mali IOTL), and of course across the water into Europe. At that point your centers of gravity could indeed be Talebani Afghanistan and Algeria-Libya. Though that doesn't really take you sub-Saharan, where my money remains on the mess of ethnic Balkanization and potential religious radicalization (if you get another charismatic influence in there alongside the Sufis, much as say Pentecostalism has been the most successful Protestant incursion into the southern Americas) that we still choose to call "Somalia" because we insist on the tidiness of nations.