Does the google mini only control the one lightbulb or does it have the capablity to control more? If so how many lights can it control?

Not sure if there's a top limit; we have four separate smart bulbs we control independently or in groups.

You can control every device that is set up in your Google Home app. The bulb is just included, I'm guessing for someone who doesn't have any smart home devices yet and want to get started.

It can work with as many lights as you want in the same room or nearby. Each light can be controlled individually or in groups depending on how you set them up.

It has the ability to control multiple smart devices and multiple smart light bulbs. You can control multiple devices in multiple rooms.

The Google Home Mini (and other Google Home devices) can control many lights and other devices (plugs and switches). Don't recall exactly how many it can control, but it is a lot.