Shoshanas Chasidim
This niggun, to the words of the Purim piut, Shoshanas Yaakov, is attributed to the Chassidim of the Alter Rebbe. They composed it in honor of the Yud Tes Kislev geulah, after the Alter Rebbe was liberated from prison. They sang the words differently than the the usual poem sung after reading the Megillah - substituting, for example, “Shoshanas Chassidim” instead of “Shoshanas Yaakov” and “ticheles Admu”r” instead of “ticheles Mordechai”.
This niggun is sung on both Yud Tes Kislev and Purim.