Exodus 23:29
I won't drive them out before you in a single year, so that the land does not become desolate and so that wild animals do not overrun you.
Deuteronomy 7:22
He slowly will dislodge these nations before you, but he won't destroy them quickly, so the wild animals won't multiply around you.
Joshua 15:63
Now as for the Jebusites who lived in Jerusalem, the descendants of Judah could not expel them, so Jebusites live with the descendants of Judah in Jerusalem to this day.
Joshua 16:10
However, they did not drive out the Canaanites who lived in Gezer, so the Canaanites live within the territory of Ephraim to this day, but they serve as forced laborers.
Joshua 17:12-13
The descendants of Manasseh did not take possession of these cities, because the Canaanites predominated in that territory.
Judges 3:1-4
Here's a list of nations that the LORD caused to remain in order to test Israel (that is, everyone who had not gained any battle experience in Canaan)