In the modern business world, smaller companies are often gobbled up/incorporated by larger corporations. Similarly, entrepreneurs might spin off new independent companies after leaving a large corporation. A similar phenomenon occurred among the wulin sects of wuxia fiction.
Let's compile a list of such sects.
Western Shaolin: Spin-off of the Shaolin Temple. No martial arts, however, just religion.
Diamond Men: A martial arts spin-off school of Shaolin Temple.
Mo Dong Sect: Technically speaking, a Shaolin spin-off school because its founder (Cheung 3 Fung) had once been a Shaolin member. It took on such a different character from its "parent," however, that it's hard to think of it as a spin-off.
Celestial Eagle Sect: A spin-off of the Ming Cult. Later reincorporated into the Ming Cult.
Mo Leung Sword Sect: I just learned from CC that this sect *might* have been incorporated into the Siu Yiu Sect.
Sing Suk Sect: A spin-off of the Siu Yiu Sect.
Any other such sects you can think of?