Sayings in Reference to Gentiles in Talmudic and Medieval Jewish Writings

Kill the best of the heathens (gentiles):

R. Simeon b. Yoḥai taught: Kill the best of the heathens in time of war; crush the brain of the best of serpents. The most worthy of women indulges in witchcraft. Happy is he who does the will of the Omnipresent. Tractate Soferim 15b.10

A Jew may convert a non-Jew and circumcise him, but a Jew is forbidden to heal a non-Jew, etc.

The subsequent passages argue over whether or not a non-Jew can be permitted to circumcise a Jew. 

Non-Jews to Receive Death Penalty for Studying Torah [No wonder Christians from early times wrongly taught the abandonment of the Law]:

And Rabbi Yoḥanan says: A gentile who engages in Torah study is liable to receive the death penalty; as it is stated: “Moses commanded us a law [torah], an inheritance of the congregation of Jacob” (Deuteronomy 33:4), indicating that it is an inheritance for us, and not for them.

The Gemara challenges: But if so, let the tanna count this prohibition among the seven Noahide mitzvot. The Gemara explains: According to the one who says that the verse is referring to the Torah as an inheritance, this prohibition is included in the prohibition of robbery, as a gentile who studies Torah robs the Jewish people of it. According to the one who says that the verse is referring to the Torah as betrothed, as the spelling of the Hebrew word for betrothed [me’orasa], is similar to that of the word for inheritance [morasha], the punishment of a gentile who studies Torah is like that of one who engages in intercourse with a betrothed young woman, which is execution by stoning. - Sanhedrin 59a.2-3

Gentiles are not "man" - a misreading of Ezekiel 34:31:

The amora proceeded to ask Elijah a different question and said to him: Is not the Master a priest? What is the reason that the Master is standing in a cemetery? Elijah said to him: Has the Master not studied the mishnaic order of Teharot? As it is taught in a baraita: Rabbi Shimon ben Yoḥai says that the graves of gentiles do not render one impure, as it is stated: “And you, My sheep, the sheep of My pasture, are man” (Ezekiel 34:31), which teaches that you, i.e., the Jewish people, are called “man,” but gentiles are not called “man.” Since the Torah states with regard to ritual impurity imparted in a tent: “If a man dies in a tent” (Numbers 19:14), evidently impurity imparted by a tent does not apply to gentiles. – Bava Metzia 114b.2

Jews may withhold the wages of gentiles, even if it is considered "robbery":

Rather, Rav Aḥa, son of Rav Ika, says that there is a different explanation: It is necessary only to teach the halakha of one who withholds the wages of a hired laborer; for a gentile to do so to another gentile and for a gentile to do so to a Jew is prohibited, but for a Jew to do so to a gentile is permitted. This case is less obvious than other types of robbery, as instead of taking an item from the victim, the robber withholds money that is due to the victim. - Sanhedrin 57a.22

Gentiles are not authorized to take beautiful women as war booty, and they are not authorized to conquer:

The Gemara asks: And is there not? But isn’t there the permission for a Jew to take a married beautiful woman, who was taken as a prisoner of war, to be his wife? For a gentile to do so is forbidden. The Gemara answers: There, the reason gentiles are prohibited from doing so is because they are not authorized to conquer. It is not permitted for gentiles to wage wars of conquest, and the halakha of marrying a beautiful woman is stated only with regard to a war of conquest. Therefore the fact that a beautiful woman who is a prisoner of war is permitted only to a Jew and not to a gentile does not indicate that gentiles have a higher degree of sanctity.

For more, see Twisted Jewish Reasoning and the Source of the So-Called "Noahide Laws" where Jews do not suffer punishment for murdering non-Jews, and where it is permissible for Jews to rob non-Jews.