Judaism
Around the 1st century CE, there were several small Jewish sects: the Pharisees, Sadducees, Zealots, Essenes, and Christians. After the destruction of the Second Temple in 70 CE, these sects vanished. Christianity survived, but by breaking with Judaism and becoming a separate religion; the Pharisees survived but in the form of Rabbinic Judaism (today, known simply as "Judaism"). The Sadducees rejected the divine inspiration of the Prophets and the Writings, relying only on the Torah as divinely inspired. Consequently, a number of other core tenets of the Pharisees' belief system (which became the basis for modern Judaism), were also dismissed by the Sadducees. (The Samaritans practiced a similar religion, which is traditionally considered separate from Judaism.)
Islamic schools and branches
Shia Islam, on the other hand, is separated into three major sects: Twelvers, Ismailis, and Zaydis. The vast majority of Shias are Twelvers (a 2012 estimate puts the figure as 94% of Shias being Twelvers) to the extent that the term "Shia" frequently refers to Twelvers by default. The Twelver Shias are also notably the only sect of Muslims that complies with the saying of Muhammad that he would have twelve successors, a saying accepted by both Shia and Sunni Muslims.