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.)
Sephardic Bnei Anusim
In the last 5 to 10 years a growing number "of [Sephardic] Benei Anusim have been established in Brazil, Colombia, Costa Rica, Chile, Ecuador, Mexico, Dominican Republic, Venezuela, and in Sefarad [Iberia] itself" as "organized groups." Some members of these communities have formally reverted to Judaism, operating as functional communities of public Judaizers. For more information on these groups, please see Neo-Western Sephardim.