Were any of the Greek philosophers against slavery and for women's rights??

Several of the Greek philosophers opposed slavery in some or all forms, and some also argued for gender equality.
Aristotle believed in a concept he termed "natural slavery". In other words, he believed that some people (such as pale, sluggish northerners made dull by the cold climate in which they lived) were best suited to be slaves, while other more rational people were best suited to be masters. He thought that enslaving someone who was not a "natural slave" was wrong. He also believed that women were naturally inferior.
Plato was a far more unconventional philosopher. He admitted women and slaves into his Academy. In fact, Hypatia, a woman, was actually the leader of the Platonic Academy in Alexandria. Chronicles of the Platonic traditions in philosophy, including Iamblichus's On the Pythagorean Way of Life and Eunapius's Lives of the Philosophers and Sophists, discuss several leading female philosophers in the Platonic/Pythagorean tradition. The reason for this is that for Platonists, the soul matters, and our corporeal nature does not. Plato argued that a "masculine" soul could be in a female body and vice versa. Also, several philosophers in this tradition believed in reincarnation. For them, the soul was permanent, and the body was simply something it inhabited temporarily; thus, judging people by the temporary corporeal form their souls inhabited (whether female or male, slave or aristocrat) was simply unphilosophical.
The Cynics believed that such things as class and gender were social conventions that did not exist in nature, and thus they considered conventional gender roles and social prejudices irrational. There were several leading female Cynics, of whom the most distinguished was Hipparchia of Maroneia.
Finally, one should note that many early Christian communities opposed slavery and stood up for women's rights, although the branch of "proto-orthodox" Christianity that gained power by the third century, alas, was not among them. St. Paul, in Galatians 3:28, said, "There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus."