Since HA is so versatile in ways of communication protocols, there are a lot of options and as Nathan states, I think most of the users have smart bulbs or switches.
You might have a look at this: 32 channel ethernet relay module – KinCony KC868-H32
I’m using the 16 port version but there were some hurdles to get it running without problems.
Another options is KNX but that comes with a serious bill.
You just might have to do some reading