3rd gen 4runner big plate switch adapter. I havent found anything useful for this slot, so i decided to dedicate it to a battery volt meter.
I found the plate on Printables, and editied it on tinker cad to accept the meter. Props to @TravisBailey_1311887 for the plate. The volt meter is on amazon. Links below.

Meter - https://www.amazon.com/Linkstyle-Digital-Voltmeter-Voltage-Battery/dp/B0DB55HD4P

Plate - https://www.printables.com/model/1485176-third-gen-4runner-large-switch-panel