I have updated the How To article on alternatives to groovy virtual devices after @wags1 suggested using a $10 LIFX WiFi bulb. Note that this cannot be used to trigger Alexa routines, but it can be used with the Home Control buttons on a Harmony remote.
For discussion of this and other virtual device options after groovy, see
Alternatives to virtual switches and sensors
Note that we still don’t have any official information on what official feature options will be available for those that do not have a SmartThings/Aeotec hub (since they can’t run Edge Drivers).