OK replied in haste from my phone. So yes, some are going to be cloud only, but not Hue. @dago5252 You have a Hue starter kit. I don't know what this means exactly, but it has to at least include a Hue Bridge and Hue color bulb. So that can be controlled by the Hubitat Hue Integration, which means that control of the Hue Bridge will be via your local IP. No need for cloud control, but devices like Google Home can still control it via the cloud. It's still going to be better to connect the Hue Bridge to Hubitat via the Hue Integration and then control it via Google Home by connecting Google Home to Hubitat. Otherwise, it does work without connecting Google Home to Hubitat, but the status updates are slow due to the Hue cloud connection.
Nest Integration is coming. Some have it, but there were limited slots available when it was first released. I don't think the Hubitat team ever fathomed that Google, or Alphabet or whomever is responsible for approving this integration for everyone to use, would be as slow as they have been. It's not Hubitat limiting it. However, if you sign up for a developer account, you can get that integration working. Just need to talk to support if you're up to the extra steps needed to get that working.
Harmony has no official integration at this time. There are community methods and workarounds. Several of them. Do some searching of the forum and decide which suites you best. Personally, I don't integrate my harmony with Hubitat. Personal choice. I sometimes watch movies or TV with lights on, sometimes they're off. I prefer to choose what I want and then just tell my voice assistant to do it, or I just use the Xiaomi button I have in my living room to set the lights.
If there are other devices you have not mentioned, please let the community know and someone will reply with a suggestion or opinion.