One of the most obvious examples of an emergency-minded smart bulb is BeOn, a connected light that's almost exclusively focused on safety and security. Each bulb has a built-in microphone that you can train to listen for the sound of your alarm system. If it ever goes off, the bulbs will come on. They'll also listen for your doorbell, then turn on if they hear it to help fool potential intruders into thinking you're home when you're not.
Philips Hue's color-changing smart bulbs have an obvious novelty appeal. And if you pair them up with the Nest Protect Smoke Detector, they'll automatically switch to the shade that makes it easiest to see in smoky conditions if something is amiss.
Generic, low-cost smart bulbs like the Cree Connected LED don't offer native, built-in emergency lighting features, but they'll work with larger systems like SmartThings. Sync them up as part of a DIY security setup, and you'll be able to set your lights to turn on automatically if a motion sensor catches someone sneaking into your home.
There's a lot of potential for Apple HomeKit to offer comprehensive smart lighting solutions that can help light the way during an emergency, but the features haven't been well implemented yet. If safety-minded lighting is your game, give HomeKit a little more time before buying in -- other systems like Nest and SmartThings are further ahead at this point.