Here’s a hack for the home control buttons.
First, to make sure we’re all talking about the same thing, this only applies to the Harmony remotes that have the special “home control buttons,” special buttons that don’t use the Harmony activities paradigm. These buttons have light bulb and plug socket icons.
Harmony provides integrations from the Harmony side for LIFX, Lutron, Philips Hue, and SmartThings for these special buttons, but the SmartThings integration is a groovy smartapp and, as mentioned above, that dies when the groovy cloud is shut off.
But the other brand integrations should still work, at least for now.
So…you can use a hue bridge with real hue devices as a proxy for ST integration. Or you can even use a hue bridge emulator, of which there are many, but of course then you have to have something running it.
I’m not saying this is a good solution, and the cost and complexity depends on the details of each use case, but it’s definitely doable. In fact, a hue bridge emulator is exactly how Home Assistant integrates with the home control buttons on a Harmony remote.
I wouldn’t think this would be worth it for most people, but if it’s really important to you to maintain that functionality (say you have a child on the autism spectrum who uses that remote to turn lights on and off), it can be done for now. 