Passive coolers (unpowered). These insulate the contents of the box from external heat, with an insulative layer which doesn't conduct heat well: typically a dense polystyrene foam (like cavity wall insulation). The simplest example is the basic Thermos or vacuum flask, which prevents heat transfer using a vacuum layer. It's not practical for large coolboxes to use a vacuum, so they use this more durable solid layer.
As air is a poor insulator, an insulated cooler always performs better with less void space inside. Best performance comes from pre-cooling the contents and packing with multiple freezer blocks. Crumpled newspaper can also be used to fill void space.
Coolers like these are popular for beach parties and fishing trips, particularly the Coleman Xtreme range which has larger volumes like the 70QT and 100QT.