Whenever adding new devices (especially light bulbs) I find that I often add devices of a type that I already have installed. Either when adding a new lamp with multiple bulbs, or replacing a defective bulb. In these cases it can be cumbersome to find the device in a large list, often with multiple bulbs with identical icons and only a device ID being slightly different (e.g. Namron bulbs).
My suggestion to help improve the experience is to be able to do one or more of the following (in my personally preferred order):
A) Filter the device list and show only device types already installed
B) List last added device(s) in the top of the list
C) Mark any installed devices in the list with a badge of some sort making it easier to locate.