Sengled Color + and Sengled Element Classic
The preferences offer a transition time of "ASAP".. instant on.
The nice thing about Sengleds are they do not act as repeaters since they can be physically powered off which messes with the zigbee mesh network.
@Ryan780 found this deal on Amazon:
You also get the hub which can be used to upgrade the firmware on the bulbs and is not needed for normal operation.
