One that I have been experimenting with is using analog phones (including rotary ones!) to act as the satellites. I live in an older home and have phone jacks in most of the rooms already so I only had to use a single analog telephone adapter. [0] The downside is I don't have wake word support, but it makes it more private and I don't find myself missing my smart speakers that much. At some point I would like to also support other types of calls on the phones, but for now I need to get an LLM hooked up to it.

[0] https://www.home-assistant.io/voice_control/worlds-most-priv...