The Empire of Nader Shah. The Afsharid Dynasty barely outlasted the death of Nader Shah's immediate heir -- even though Nader Shah was not just a great conqueror, but also a great administrator and state-builder. His administrative and military reforms endured long after his dynasty did. In another timeline, his dynasty might have even converted Persia back to Sunni Islam, or at least reconciled with Sunni Muslims on certain doctrines; he was born a Sunni Afghan, and he wanted Persia -- isolated as it was in the Ummah -- to participate in diplomacy with other Muslim nations on equal footing, even going so far as to recognise the Ottoman Caliphate.
Also, various Anatolian cultures and nations. Anatolia was home to a lot of great empires (Hittite, Persian, Macedonian, Roman, Byzantine, Seljuk, Ottoman), but it was also home to various "second-place" empires that could have been a lot more influential if things had gone differently. Lydia comes to mind; so do the Armenians, at various points in their history; various early Islamic frontier dynasties, like the Marwanids; any of the Anatolian Beyliks which weren't the Seljuks or the Ottomans, such as the much-celebrated Danishmendids or the Smyrna-based maritime state of Chaka Bey, who pioneered the corsair tradition which the Ottomans would later take up.
Most interesting, however, might be the republican Ahi Beylik of Ankara, organised around the network of Sufi orders, ghazi warriors, and guilds known as Akhiya ("Brotherhoods"). Though the Ahi state did not control much territory, Ahi brotherhoods held influence over trade, religion, and law across Anatolia and beyond, rather like Venice or Genoa. Emerging after the Seljuks were defeated by the Mongols in 1243, it's not impossible to imagine a scenario where -- in the power vacuum left by the Seljuk collapse -- Ahi guilds/holy orders take charge of things instead of regional princes.
In a similar vein, the Ikko-Ikki of Sengoku Japan; the Knights Hospitaller of the Levant, Rhodes, Malta, and the Caribbean; and the Assassins of the Levant and Persia were all fairly insular military societies, dedicated to religion, who controlled states in their own right. If the Teutonic Knights could become Prussia, how could these orders turn themselves into hegemonic, territorial states? Arguably, the Qizilbash pulled a "Prussia" when they formed Safavid Persia; and likewise for the Tijaniyya Sufi Order during the Fulani Jihads (forming states like the Sokoto Caliphate or the Imamate of Futa Jallon), or the Senoussi Sufi Order in Libya, or the aptly-named Dervish State in Somalia.
Also, various Anatolian cultures and nations. Anatolia was home to a lot of great empires (Hittite, Persian, Macedonian, Roman, Byzantine, Seljuk, Ottoman), but it was also home to various "second-place" empires that could have been a lot more influential if things had gone differently. Lydia comes to mind; so do the Armenians, at various points in their history; various early Islamic frontier dynasties, like the Marwanids; any of the Anatolian Beyliks which weren't the Seljuks or the Ottomans, such as the much-celebrated Danishmendids or the Smyrna-based maritime state of Chaka Bey, who pioneered the corsair tradition which the Ottomans would later take up.
Most interesting, however, might be the republican Ahi Beylik of Ankara, organised around the network of Sufi orders, ghazi warriors, and guilds known as Akhiya ("Brotherhoods"). Though the Ahi state did not control much territory, Ahi brotherhoods held influence over trade, religion, and law across Anatolia and beyond, rather like Venice or Genoa. Emerging after the Seljuks were defeated by the Mongols in 1243, it's not impossible to imagine a scenario where -- in the power vacuum left by the Seljuk collapse -- Ahi guilds/holy orders take charge of things instead of regional princes.
In a similar vein, the Ikko-Ikki of Sengoku Japan; the Knights Hospitaller of the Levant, Rhodes, Malta, and the Caribbean; and the Assassins of the Levant and Persia were all fairly insular military societies, dedicated to religion, who controlled states in their own right. If the Teutonic Knights could become Prussia, how could these orders turn themselves into hegemonic, territorial states? Arguably, the Qizilbash pulled a "Prussia" when they formed Safavid Persia; and likewise for the Tijaniyya Sufi Order during the Fulani Jihads (forming states like the Sokoto Caliphate or the Imamate of Futa Jallon), or the Senoussi Sufi Order in Libya, or the aptly-named Dervish State in Somalia.