Koogeek has been selling hub-less HomeKit light bulbs. It’s been making a lot of HK based products, so I’m actually a bit surprised to see that some people don’t know that the bulbs exist.
Like mentioned LIFX and LIFX+ (Generation 3) A19 and BR30 bulbs are HomeKit enabled as of Sept 21st. I'm sure there are others as well.
However keep in mind if you need/want a lot of bulbs the hubless options tend to get more expensive since all the circuitry is built in. Although I hate adding more freakin' hubs, I was ok with it for lighting. For me thats much better that 15 additional devices on my WiFi.
AppleTV (or iPad or soon HomePod) are for accessing HomeKit devices when your primary iOS device is off your WiFi network. Thats how it works for my devices, so I'm assuming others are the same.