One of those switch-blanks is used on the Limited: to enable / disable the automatic running-boards, I think. They extend out. and retract on the Limited.
The leftmost switch-blank in your case is used on my Canadian TRD Pro Off-Road: to heat the lower portion of the windshield so the wipers don't stick in the ice and snow. I see yours has the windshield-heater too, but on the far-right (as opposed to my far-left).
Those are the only factory options I can think of, for the first two switches in that row to the left of the inverter power-selector. I do think Toyota puts in wires and connectors that are only selectively used in differerent trim-levels or markets.