Intermarriage

"You shall not make marriages with them"Deuteronomy 7:3.

It is forbidden to marry a non-Jew.

Marriage with an Ammonite or Moabite

"An Ammonite or a Moabite shall not enter the congregation of G‑d"Deuteronomy 23:4.

It is forbidden to marry a male Ammonite or Moabite, even after they convert to Judaism.

Rejecting an Egyptian

"Do not reject an Egyptian"Deuteronomy 23:8.

It is forbidden to utterly distance an Egyptian convert. A third generation Egyptian convert must be allowed to marry among the Jewish people.

Rejecting an Edomite

"Do not reject the Edomite, since he is your brother"Deuteronomy 23:8.

It is forbidden to utterly distance an Edomite convert. A third generation Edomite convert must be allowed to marry among the Jewish people.

Marrying a Bastard

"A mamzer shall not enter into the assembly of G‑d"Deuteronomy 23:3.

A child born of certain illicit relationships is called a mamzer. Such an individual may not marry a non-mamzer.

A Castrated Man

"A man with injured testicles or whose member is cut may not enter the assembly of G‑d"Deuteronomy 23:2.

A man whose genitals have been damaged to the point that he is incapable of fathering a child may not marry a Jewish woman.

Castration

"...neither shall you do this in your land"Leviticus 22:24.

It is forbidden to cause castration to a male – whether human or animal – by damaging his genitals. It is forbidden even to further damage the genitals of a male who has already been castrated.