Sengled bulbs mentioned above support these commands. Most Zigbee bulbs do. Many (all?) Z-Wave bulbs do too, but there aren't as many of those. But if you're controlling more than one bulb at a time, Zigbee groups don't support this, so you're back to using commands to individual bulbs, which might result in a slight "popcorn effect" (uneven timing), though this still works well in my experience. What I don't like about the current behavior of most of these is that they'll dim down all the way to off if you don't stop it sooner (enter: popcorn effect, so different bulbs in a fixture could be off while others are on).