After Joshua's campaigns, the Anakim survived only in Gaza, Ashdod and which other city?

Answer: Gath

Joshua wiped out the Anakim from the hill country, including Hebron; only in Gaza, Gath and Ashdod did any survive.

“At that time Joshua proceeded to eliminate the Anakim from the hill country of Hebron, Debir, and Anab, and from all the hill country of Judah and of Israel. Joshua devoted them to destruction, along with their cities. No Anakim were left in the land of the Israelites; only in Gaza, Gath, and Ashdod did any survive.”— Joshua 11:21-22 (BSB)