I got this 53 quart cooler/freezer off Amazon and it fits in the bed below my tonneau cover. I picked it because it was the only one that had independent control of the freezer and fridge zones, bluetooth app control and a removable divider that lets you use the entire cooler as a freezer or fridge.

The Ecoflow Glacier looks pretty cool and has an icemaker, but it's over twice the price of the one I bought.