Surely I’ll be missing some but:
- 21 lights
- Vacuum
- Smart TV
- 6 echo devices
- Broadlink
- 14 flic buttons + 2 flic hubs
- Smart thermostat
- 25 zigbee sensors and some devices (motion,light,door,temp,etc)
- 2 aroma diffusers
- Air purifier
- Dehumidifier
- 5 smart plugs
- waterproof shower speaker
- tablet for lovelace
- Mesh wifi router
There are some other devices than came alongside the smart home project but they don’t connect to HA so they don’t affect performance, for example:
- Touchless soap dispensers
- Tooth paste dispensers
- Automatic touchless trash can
- Ozone generator for odors (with a smartplug it interacts with the aroma diffuser)
as some have said, I didn’t expect to grow that big when I began and I encountered various problems throughout the process but after getting good hardware and good suggestions from people around here it finally runs smoothly.
Why so many?
partially because it’s addictive. Partially because the more tools you have to build automations, the smarter the house becomes, specially regarding sensors. I never have to manipulate my thermostat, dehumidifier, air purifier nor the aroma diffuser, etc. Lights behave as expected 90% of the times while me doing nothing to turn them on or off. The other 10% of the times I push a button or use a voice command… I get alerts when rooms are ventilated, washing machine is done, etc… Long story short, the more you build the lazier you become and you keep going on and on 
I need to do some maintenance maybe once or twice a month at most.