What are the least popular landing spots with good loot?

Try the Outdoor Cinema, it's not so popular and has decent loot and material. It's not marked as a location on the map. But if you look at the center, you'll see The Agency, it's a little bit North of there, just to the left of Fenzy Farm. The only thing it doesn't have is a reboot van, but there is one not so far away at Frenzy Farm.

Outdoor Cinema

Another OK quiet location is the Weather Station, located in the mountains towards the south east of the map. You'll get loads of chests and ammo, a good mix of all three materials types and a helicopter too!

Weather Station