What are some detestable practices warned against in Deuteronomy 18 9-13?

You should read Deuteronomy 18:9-13:

The Canaanites killed infants childern by burning them. This is the worst sin, to kill life that can't defend itself.

A practice to worship Moloch, Baal(s), and Asherah on the high places (same as in Ezekiel 23:36-39).

Sorcery

Divination

Communicating with the dead.