Light bulb icon appeared in the menu bar

Do you have the Hue menu installed? It will show a light bulb icon and lets you control the color of lights:

https://www.cultofmac.com/242842/hue-menu-lets-you-control-philips-hue-bulbs-from-the-comfort-of-your-mac/

The stuff shown to the left of the Bluetooth icon is all locally-added software.

Click on the status menu lightbulb item, and see if what it is can be revealed by what it offers.

I find several different apps with lightbulb-inspired icons, but not that particular icon.