Answer:
   
   So far, the FAQ has mentioned Lubavitch, Breslov, and Satmar. However,
   there are lots of forms of Chasidism (and, alas, before the Shoah,
   there were even more). Some of the better known forms not discussed so
   far include: Amshinov, Alecsander, Belzer, Bobover, Bostoner, Boyaner,
   Ger (Gur), Karlin-Stoliner, Kloisenberger, Lalover, Modzitzer,
   Muncatz, Pupa, Radziner, Skvirer, Slonimer, Spink, Tauscher, and
   Vizhnitzer. In Israel the Gerrer Hasidim are probably the most
   numerous, followed by the Belzers, Vizhnitzers, and Lubavichers. In
   addition, there are small sub-groupings like the Toldos Aharon
   haredim, who share many traditions with Satmar. Quite a few of these
   follow the Satmar position on not recognizing the Zionist state, such
   as Spink, Pupa, Toldos Aharon/Toldos Avrohom Yitzchak, Tseihelm, etc.
   as well as non-Chassidic communities such as Brisk and many
   'Yerushalmi Litvish'.
   
   Chasidism was founded by Rabbi Israel Baal Shem Tov, who lived in
   Poland and Ukraine in the early 1700's. He travelled from village to
   village, having different students in each. These students later
   founded schools... and over time, these various schools became the
   different forms that we see today. Each form is centered on the
   teachings of a particular Rebbe. The forms are usually named after the
   Rebee's town. The differences among the forms can be in worship style,
   customs, dress, philosophy, or political views.