An UV light sensor could be the GUVA-S12SD.
According to the datasheet it is sensitive for 240 to 360 nm, and it is linear with the amount of UV light.
You can not place it under a plastic transparent lid of the box. That would reduce the UV light too much.
Search on Ebay for "uv sensor", some are 8 dollars.
The "REYAX UVI-01", "ZY-6" and "PT-6" are used in the same way.
They are used as a solar cell, it produces a voltage. But the impedance of the circuit is 1M and it is 15% inaccurate.
You can add a lightning sensor and a sound level sensor to your list.